score:4
First, I wouldn't count on the train arriving on time. It's a long, long way from Chicago, and on those transcontinental trains, minor delays tend to stack. My rule of thumb is 1 hour delay per 10 hours running time from the origin, so brace yourselves for 1-2 hours late.
This is normal. If you took a German ICE train or Japanese Shinkansen schedule and and made it circumnavigate its country a few times so it racked up 30 hours of travel without any recovery time, it would also fall down 3 hours. Stuff happens.
This uncertainty annoys many travelers, but seasoned Amtrak travelers take it in stride because it's a small price to pay for such a nice mode of travel... if you plan for it, which it sounds like you did.
While it looks like Fargo has a fine old station, it only gets 2 trains a day ( the other being the eastbound Empire Builder arriving nominally 2 hours before your westbound, but by the 10% rule of thumb, 3-5 hours late is likely). In these scenarios, Amtrak typically only staffs the station when trains are due, so after the later of the two trains arrives, they will want you to leave the station so they can lock up and go home. Of course if the eastbound is late and expected, they won't mind you being there.
Like many old stations it is right downtown, but that doesn't mean downtown is open.
As far as a 24 hour restaurant, this may help. Denny's doesn't look like walking distance, but Fryn' Pan restaurant is about 3000β (0.6 mi.; 1000m) away.