How would an SS officer travel from Auschwitz to Berlin?

Some aspects can and have to observed for that endeavour, some cannot, some just can't be provided by me now, but some you are also free to invent.
Of course, try to be careful with what to 'invent' if writing such a story and around that topic.

First, the physical aspects:

_{Wikipedia: KZ Auschwitz}

We see that the actual train rails lead to Kattowitz/Berlin.

The actual lines, transit stops, and schedules then would be for civilian trains found here:

Deutsches Kursbuch: Jahresfahrplan 1944/45

Most of the rest is now up for interpretation and 'artistic freedom'?

What kind of officer, on what kind of 'mission'? A Gruppenfüher on his way to his holidays, or something urgent and official? In the latter case, flying or by car would probably more realistic.

He could travel with military transports or civilian trains. A schedule would have to be observed in any case, as no special train would be provided for one officer. If it was a civilian train, civilians might sit in the same car, on a military transport: of course not. Even death transports would have had a car with guardsmen and those could make a little room for one more on board?

As Auschwitz was located at the border to the Generalgouvernement – that part of Poland occupied but not fully annexed to the Reich – but the complex being inside the new borders of the Reich, he would not cross a border, thus not being subject to a single one control of the borders, whether in uniform or not. Other controls might be of course another option for a totalitarian police state.

Travel time approximation is not that different from today, as the trains, their speed and the rail capacity didn't improve much since the 1930s, often to the contrary.
From Berlin to Kattowitz it would take around 6–7 hours now, from Oswiecim to Berlin it would take around 8–9 hours now.

Perhaps of some interest as well would be the historical novel by Peter Wyden: "Stella", Simon & Schuster: New York, 1992. The main character is Stella Kübler.

Update on the situation in Breslau:
Volkspolizei was never in Breslau, as this would be specific to the Soviet occupation zone and only founded in October 1945.

Western bombers reached Breslau for the first time on 7 October 1944. IN 1941 one Soviet raid dropped a few bombs earlier, but targeting the train station didn't do much damage.

Most 'interesting' for the purpose of such a novel would probably be the fact that two camps that belonged to Groß-Rosen were established near the city for the use of forced labour in mid 1944.

Some number material lifted from a dissertation would be on Deutsche Verwaltungsgeschichte Schlesien, Breslau

As to the most salient features during that time:

Roughly 2,500 of Breslau’s Jews were arrested during the November pogroms and sent to concentration camps. Most of the Jews who had not yet left the city now intensified their efforts to arrange for emigration as speedily as possible. The more than seven thousand who did not manage to emigrate were deported between November 1941 and April 1944 and murdered—most of them in Kaunus, Majdanek, Sobibor, Theresienstadt, and Auschwitz. Walter Tausk was assigned to the first railroad transport leaving Breslau on November 25, 1941, bound for Kaunas. He was presumably shot there soon after the train’s arrival.

Breslauers who were not persecuted by the Nazis and who did not see the burning of the New Synagogue as portending the demise of their city were fooled into a deceptive sense of security. The Second World War even brought to the city an odd kind of vitality. Due to its geographic location far from the bases of the British and American bomber fleets, Silesia became the destination of the Kinderlandverschickung program, an effort to evacuate children from the cities; there were as well thousands of people bombed out of their houses in the West who found shelter there. In addition, a large number of government agencies and arms factories were relocated to Silesia during the war. Breslau’s factories were expanded and converted for war production. The most significant enterprise in the city, the Linke-Hofmann works, which before the war had been one of the largest producers of railroad cars and locomotives in Europe, now shifted production to armored trains, tank parts, parts for military utility vehicles, and motors for the V-2 rockets. Breslau’s population grew by hundreds of thousands over the course of the war to reach almost one million in 1944. The city became one of the most important logistic centers for supplying the eastern front. Trains transported munitions, tanks, and other supplies from Breslau to the combat zones and returned carrying tens of thousands of wounded soldiers, who were treated in Breslau’s huge military hospitals and then sent back to the front.

The war did not become a direct threat to Breslau until the summer of 1944, when the Red Army reached the Vistula, bringing the eastern front less than two hundred miles from the city. At the same time, the Americans and British had advanced so far eastward that Silesia was now within range of Allied air raids. In the fall of 1944, in expectation of the Soviet advance, Hitler declared the unfortified city of Breslau to be a “fortress” that under no circumstances was allowed to surrender. It was to be defended to the last man. A garrison was formed of soldiers who happened to be in the city—scattered troops, those serving in the rearguard, those passing through on leave from the front, convalescing wounded—and supplemented by Volkssturm (People’s Militia) units. Civilians from the entire region were enlisted to build fortifications all around Breslau, and the city’s storehouses were stocked with everything that might be needed for an extended siege.
_{Gregor Thum: "Uprooted: How Breslau Became Wroclaw during the Century of Expulsions", Princeton University Press, 2011. (p xxi)}

That should read: the outlook on the horizon was certainly not very bright. But for ordinary citizens, life went on pretty comfortably. Food, work, shelter, daily life went on. Soldiers and other uniforms everywhere, but losses of life perceived as still 'far away' didn't affect the running of the city infrastructure. The following gives you a most concise picture of life in city:

“We were in a high spirits, but we were soon disappointed,” he recalled. “Life seemed to go on as normal and no enemy aircraft could be seen in the sky.”

And so it would be for the next five years, more or less. Breslau was not untouched by war – nowhere in Germany was – but beyond the range of enemy bombers, the city was less affected than almost any other in the Reich. There were restrictions – on travel, on food, on personal liberties – but otherwise life went on as it did in peacetime. On Sundays, the Hitlerjugend would parade through the streets singing anti-Jewish songs before marching into the Jahrhunderthalle to the sound of tympani and fanfares. Each Wednesday and Saturday, Ulrich Frodien pulled on the uniform of the Jungvolk, and from the age of fourteen, the Hitlerjugend. He was “always in uniform, always in a column”. Some boys found it a chore, some spellbinding, but putting on that uniform invariably made Breslau’s youths slightly c**ky. Riding home on the tram to Karlowitz, three miles from the city centre, Hans Henkel watched a group of boisterous Hitler Youths climb on board. One youth stared through the glass partition at the passengers, most of them elderly. “That’s right,” the boy yelled. “The cemetery fodder sit down while Germany’s future stands.” There was an awkward silence in the carriage, then an elderly gentleman stood up, approached the c**k-sure youngster and slapped him in the face. Striking a Hitlerjugend in uniform was a criminal offence, but no one intervened.

The lively nightlife for which Breslau was renowned continued, although the strict black-out meant that trams and cars drove through the streets with their lights dimmed and the streetlamps were out; Breslauers wore luminescent badges to avoid bumping into each other in the dark. The restaurants, the theatres, the bars, the cinemas remained open. Most weeks, Ulrich Frodien headed into town to catch a film. He particularly enjoyed historical dramas, of which there were many: Ritt in die Freiheit, the story of a 19th-Century Polish uprising against the Russians, Der Grosse König, an award-winning biography of Frederick the Great, or Ohm Krüger, an account of the Boer War laden with anti-British vitriol. And before each main feature, the Wochenschau, the weekly newsreel, a pot pourri of events at home – engineers at work in Silesia’s steel mills, large-scale Nazi ceremonies, submariners skiing in the Alps – and events at the front – the bombardment of Warsaw, mountain troops in Narvik, the fall of Paris.

Frodien watched the newsreels avidly, but it was only years later that he realized how sanitized a picture of war they presented. There were shots of “carefully-erected birch crosses with a steel helmet on top, pretty nurses and recuperating soldiers in the hospitals,” or graveside ceremonies with heroic speeches and guards of honour. But of the dead themselves, nothing. “No shot-up panzers, no shot-down aircraft, no bombed flak position,” he recalled. What propaganda tried to hide, life could not. Willy Cohn was struck by the large number of women walking around Breslau, their faces covered by black veils. “All widowed by the war – most of them not reported in the newspaper,” he observed in his diary. And occasionally, there were direct reminders of the war raging across Europe.

In mid-November 1941, Breslau was bombed in broad daylight. The sum total of seven bombs fell on the city (one of those was a dud), but ten people were killed. The Schlesische Tageszeitung immediately branded the Soviet attack a ‘terror raid’ aimed at defenceless civilians. “In fact, the attack was aimed at the Hauptbahnhof – and struck very close to it,” Willy Cohn noted. At least one bomb landed in the station, tearing both legs off a woman. “War always affects the innocent but this air raid is also proof that the enemy is now catching up.”

The enemy was not catching up quickly enough for Willy Cohn. One week after that entry in his journal, he was arrested with his wife and two children. They joined a train carrying another 1,000 Breslau Jews to Kaunas in Lithuania. Before November was out, the Cohn family had been exterminated. Walter Tausk too. He was also shipped to Lithuania with the first transports. Over the coming eighteen months, trains would leave for camps at Auschwitz, Majdanek, Sobibor, Belzec in Poland and Theresienstadt in Czechoslovakia under what was cynically called the ‘Jewish Resettlement Action’. By the summer of 1943, the authorities could proclaim Breslau Judenrein – cleansed of Jews.

It wasn’t merely the deportation of the Jews which changed the demographics of Breslau as the war progressed. By the spring of 1944, nearly half a million Germans had been relocated from western and central Germany to Silesia, which quickly earned the nickname Luftschutzkeller Deutschlands – Germany’s air raid shelter. With the people came industry which also sought to escape the grasp of Allied bombers. Despite the Nazi’s much-trumpeted Volksgemeinschaft – national community – Breslau’s womenfolk did not welcome the influx of refugees, not least because they quickly emptied shops and stores of underwear and bedding.

What Breslauers resented more, however, was the influx of foreign labourers – French, Russian, Polish prisoners of war, Czechs, concentration camp inmates – needed to fill the gaps left by Breslau’s men leaving for the front. There was no hiding these new arrivals: Poles wore armbands branded ‘P’ and carried identity cards with a pig stamped on the reverse; White Russians wore a badge on their upper left arm bearing their national colours, white, red, white; Ukrainians a blue-yellow badge with a trident, the coat of arms of the ancient state of Kiev under Vladimir the Great; and Russians were marked by a white-blue-red badge featuring the cross of St Andrew. None was the equal of a German – as Breslauers constantly reminded these captive peoples. They were infuriated when prisoners of war marching to and from camp did not make way for them in the streets. They were even more infuriated when they watched Russian labourers hanging around for fifteen minutes or more at a time doing nothing. Poles, Ulrich Frodien observed, were “treated worse than farm dogs. They had become fair game, whipping boys for every thug in the village police, worked until every last ounce of strength had been squeezed out of them, and despised even more than the lowliest German village idiot.” Foreign drivers on the trams – also branded by armbands – grew rather too close to the young Breslau women serving as conductors for the liking of many.

Fraternisation with these foreigners was not merely frowned upon – it was a criminal offence; girls could be fined 10 Reichsmarks merely for drinking and dancing with Polish prisoners in a bar. A twenty-three-year-old housewife who befriended and then had an affair with an English prisoner, helping him escape, was jailed for four years, while a labourer who passed letters between a captured Soviet soldier and a female Russian worker – letters which were “hostile to the state” – was sentenced to two years in prison. The penalties for foreign labourers who transgressed were far more severe, however. Twenty-year-old Marian Kaczmarek laid track for the Reichsbahn, the state railway. After repeated beatings by his German foreman, Kaczmarek struck out. His temper cost him an additional six years of hard labour. The punishment was too mild for Breslau’s chief prosecutor; he imposed the death penalty.

Working on farms, on the trams, on the railways, all demanded forced or foreign labourers, but never in the numbers required by the armaments industry. A dozen forced labour and concentration camps grew on the periphery of the city to meet the demands not just of Breslau firms such as Linke-Hofmann and FAMO – producing parts for the V2 rockets and panzers, respectively – but other industry which began relocating to the area as the bombing of the industrial heartland of the Ruhr intensified. Three slave camps fed the Rheinmetall-Borsig ammunition works at Hundsfeld, five miles north-east of the city centre, which churned out three million electric fuses for bombs in 1943, as well as ten million rounds of 20, 30 and 37mm shells and some 6,000 electrical gun sights. Three decades later and living in the USA, the works’ director, Herbert Rühlemann composed a long-winded and rather self-satisfied memoir, Father Tells Daughter. Father did not tell daughter everything, however. Less-than-honestly, Rühlemann referred to the bulk of his workforce as Gastarbeiter – guest workers. Some were, but 2,000 were concentration camp prisoners, half of them women.

Rheinmetall’s demand for labour paled compared with one armaments factory which began to take shape from the spring of 1942. The Berthawerk – named after the matriarch of the Krupp family – at Markstädt, sixteen miles south-east of Breslau, would produce up to 600 field howitzers and anti-tank guns every month, employing upwards of 12,000 people. One of its directors, Eberhard Franke, painted an almost idyllic picture of a true ‘workers community’: it was renowned throughout Lower Silesia for the quality of its food; its football team won the local league over four successive seasons; there were boxing matches at which the legendary fighter Max Schmeling officiated; there were libraries, musical instruments, films, radios provided for workers who formed theatre groups and staged variety shows for colleagues.

The reality was far less idyllic. Nearly half of the Berthawerk’s employees were concentration camp inmates. After being woken at 4.30am, they trudged for fifty minutes each morning from the nearby camp at Fünfteichen, usually in broken clogs or with rags wrapped around their feet, then worked for twelve hours. There was no breakfast, no evening meal, just a bowl of soup at mid-day. If they pushed too forcefully for their daily meal, they were beaten with a rifle butt by a guard. They were beaten too if their work did not come up to scratch – usually with a whip of iron and rubber. When there were air raids, Germans sought refuge in the air raid shelters; forced labourers remained at their posts. “We were not slaves, our status was much lower,” recalled Tadeusz Goldsztajn, a Polish Jew who was sixteen when he arrived at the Krupp works. “The equipment in the shop was well maintained. We, on the other hand, were like a piece of sandpaper which, rubbed once or twice, becomes useless and is thrown away to be burned with the waste.”

Given such treatment, it was hardly surprising hatred welled up in the Ostarbeiter – eastern worker. The security service intercepted one letter from a Ukrainian. “I submit to these Fascists, I have become their servant,” the writer sighed. “Oh, damn these years! I want my liberty, I want to fill my lungs with the fresh Russian air.” Each morning he bowed, humbly offered his hand to his masters and greeted them repeatedly. He longed for the day when the Red Army neared. “I’ll be one of the first to join the partisans or fight at the front,” he vowed. “I will be the first to shoot at their merciless hearts, those who laugh about the hardships faced by the Russian people. And all this will happen – sooner or later.”

In the broiling heat, the sweat streamed down the faces of the several dozen standard bearers, holding their banners high between a sea of outstretched hands. As the bearers took their place on the stage, Joseph Goebbels entered the Jahrhunderthalle, followed by the luminaries of the Nazi Party in Silesia and senior Wehrmacht officers. The Propaganda Minister had spent the afternoon of 7 July 1944 visiting his wife Magda in a Breslau clinic, where she was recovering from an operation on her jaw. Otherwise, he found himself frustrated away from the capital. It was nearly impossible to obtain news from the Eastern Front. No news, he reasoned, would be good news.

As Goebbels fretted, the halls and assembly rooms of Breslau began to fill this Friday evening. All 12,000 seats in the Jahrhunderthalle itself. A sizeable crowd gathered outside in Scheitniger Park. The loudspeakers he’d had erected six years earlier would carry the minister’s words outside the confines of the huge domed building to other halls throughout the Silesian capital. State radio would carry them across the Reich – and beyond.

It was one of the Goebbels’ more measured performances. He looked relaxed, leaned with one hand of the podium, put his hands on his hips, his gesticulations were less frantic than usual. He left his audience in no doubt about the gravity of Germany’s plight. The enemy had launched a general offensive in the East and West with overwhelming superiority. “If we do not throw them back now, our enemies will wipe Germany – and everything German – from the face of the earth,” he told his audience bluntly. “The German people are in danger!”

Mention of the “aerial criminals”, the Anglo-American bomber crews with names such as Murder Incorporated who were “turning German cities to rubble and ash”, was drowned out by boos. “There will be retribution,” he promised, “and when it comes, not one tear will be shed in Germany.” The 12,000-strong audience rose from their seats, shouted, applauded, stamped their feet. It was several minutes before the uproar subsided and the minister could continue. When he did, he urged the German people to summon their strength for one final push. “The hour demands a total war effort by every individual and the entire nation, using all our spiritual and material reserves.” He continued:

We National Socialists have endured and overcome so many crises and hard tests in the history of our movement and the Reich that we have never doubted our success for a moment.
The best guarantee of victory is the Führer himself. We look to him with religious faith. He will lead the nation through all dangers and tests with a sure hand. His pledge is the same as ours: a struggle which a nation stands behind with utter fanaticism can never end in anything but victory.

The organ began to play the national anthem. Inside and outside the Jahrhunderthalle, Breslauers stretched their arms out again and sang with gusto. “There’s probably no one in the crowd who’s not carried away deep down in their heart and filled with belief in a positive end to this difficult struggle,” Goebbels’ secretary Wilfred von Oven wrote fawningly.

Despite Goebbels’ assurances and von Oven’s observations, Breslauers were beginning to doubt the war would end in Germany’s favour. Outwardly, life in the city went on as usual. Every date in the Nazi calendar was still marked extravagantly with some form of rally or demonstration. There were the ‘Day of Duty for Youth’ and ‘Day of the Wehrmacht’ in March, the anniversaries of the Nazis’ flying and welfare organisations in April, there was a celebration of the tenth anniversary of the Nazi seizure of power in the Jahrhunderthalle, each Heldengedenktag – Heroes’ Memorial Day – was commemorated on the fifth Sunday before Easter with guards of honour standing in front of Breslau’s war memorials while Wehrmacht and Party leaders laid wreaths and soldiers formed up on the Schlossplatz to listen to a speech by the city’s ranking general, Rudolf Koch-Erpach. April 20, Hitler’s birthday, was celebrated of course, but by 1944 it had become a normal working day. In kindergartens, teachers still put garlands on portraits of the Führer and lit ‘Hitler candles’, however, while children sang hymns of praise and listened to stories from the life of their leader. Flags flew in the streets, pictures and busts of Hitler were displayed in shop windows and in the evening, the Ortsgruppen celebrated as 13,000 Hitler Youths marched through the city’s streets, while there was a performance of Beethoven’s Symphony No.9 in honour of wounded soldiers and workers in the armaments industry. With the arrival of summer, the outdoor swimming pools opened daily from 7am until dusk for bathers. The Cologne Radio Orchestra performed marches, dances and songs from the silver screen on the promenade by the Oder. The Liebich, Breslau’s famous variety theatre, offered Melody of Love, a quick-fire sketch show, while at the Circus Busch comedian Harry Zimmo entertained a 3,000-strong audience. At the Wappenhof, Germany’s largest open-air theatre by the banks of the Oder, patrons enjoyed a new drink, a honey-yellow apple pomace with a frothy head which tasted sweet and sour. It was particularly popular at Gandau airfield, so locals dubbed it Fliegerbier – airmen’s beer. As it had done the previous two years, the Nazi Party leadership organised the Verwundetenfahrt – trip for the wounded – to the historic town of Trebnitz, a dozen miles north of the city. There the famous Flying Trebnitzer light trains, festooned with cartoons and caricatures drawn by students of a local art school, took the men for a day out. In spite of the frivolity of the event with its marching bands and smiling girls, there was no hiding the cost of the war to Breslau. That same day the Schlesische Tageszeitung published thirty death notices of men killed in action: twenty-four-year-old Unteroffizier Gerhard Weiss, a soldier for five years, killed in Normandy; Oberwachtmeister Helmut Czembor, holder of the Iron Cross, killed in Italy during the battles south of Rome; twenty-one-year-old Obergefreiter Günter Kochner, killed in an air raid. “Anyone who knew him will understand our pain,” his grandparents eulogized. But most of the fallen listed in Breslau’s Nazi Party mouthpiece were killed on the Eastern Front – a front which was beginning to draw ever closer to the borders of the Reich. In mid-June, the German Army still held Byelorussia – Minsk, Vitebsk, Grodno. Six weeks later, the Red Army was at the gates of Warsaw and had crossed the Vistula upstream of the Polish capital at Pulawy and Baranow, less than 250 miles from Breslau. The collapse of the Eastern Front provoked alarm. “The Russians haven’t far to go now to the German frontier,” one Breslau housewife wrote. “If it gets very bad, there will be nothing left for us but the gas tap. We won’t let ourselves be deported.” She was, she said, not alone. “Many are of my opinion.” All manner of rumours circulated. Entire regiments had deserted. (They hadn’t.) Hitler had visited the front and sacked several generals on the spot. (He didn’t.) Some generals had not been killed in battle but had been executed. (They had not been.) Officers had fled the battlefield with their Polish or Russian mistresses. (They had.) Weary soldiers struggled back to German lines barefoot, without belts, tattered and torn, undisciplined. (They had.) “This retreat,” one person was overheard to say, “is one of the darkest chapters in German history.”

Even the Schlesische Tageszeitung, conceded there was an “obvious crisis in the East”. Gauleiter Karl Hanke still exuded confidence. On a visit to the historic town of Namslau, three dozen miles east of Breslau, he told the populace: “The war on the Eastern Front only interests me when the first Russians appear before Namslau.” As he spoke, thousands of Silesians were already preparing for the defence of their native soil.
_{Richard Hargreaves: "Hitler's final fortress: Breslau, 1945", Pen & Sword, 2011.}