1. DO NOT SAY YOU ARE "WORKING"

You are coming for some meetings, and then some vacation for 6 weeks. That’s all there is to it.

Say nothing else.

Regarding the fact that you "might" come home earlier – so what? You "might" do anything.

You shouldn’t really think of this question as being honest or not. There is uncertainty, yes, as in all of life, but it’s mostly you thinking ahead. You’re letting yourself be distracted from the main point that interests immigration: are you trying to sneak into the county permanently? Here you can and should be loud and clear: no. Don’t obfuscate the issue for them with dithering and contingencies.

That said, it would serve you best to have some reasonable plan to account for the longest possible stay. “I want to visit so-and-so in such and such a place, here is their name and address, and so on. And I always dreamed of seeing the Grand Canyon/New Orleans/whatever, so I’ll probably try to push on there if time allows.” And then it’d probably be useful to slip in something like “I have to be back at work by — to attend/teach/report” – whatever you can scare up. Says clearly and truthfully that you don’t have any intention to extend your stay, that you have work to return to.

Everyone is happy if you return sooner than planned, because some unfortunate thing happened and you have to go back (to work) to deal with it. Apart from you :-), but that’s not the question.

Don’t.

You have a return ticket. Talk about a trip corresponding to that ticket, and don’t confuse the issue.

Under the Visa Waiver scheme, you can stay for up to 90 days. There is no requirement to notify authorities if you choose to stay longer, so there are no legal issues with failing to tell immigration. However telling immigration that you aren’t sure when you’re leaving the country is a big red flag for them.

A personal experience. I live in the UK, and at one time I did some liaison work with Ford in Detroit. One time I was booked to have a week in Detroit, with the possibility of stretching it to 2 weeks if it turned out there was more work needed. We duly booked a return ticket which could be changed, and everything was good.

I got to immigration in Detroit, and as usual the immigration officer asked me why I was entering the country (“business meetings with Ford”) and how long I was going to be there. I said, “Probably a week, but it could be longer.”

“WHY DON’T YOU KNOW?!?!” (Exact words, at parade-ground volume.)

A brief pause from me – I wasn’t expecting that! My reply: “Because the business meetings may take longer.”

A long pause from him, clearly thinking about how much of a pain he wanted to be, then he stamped my passport and let me through. I should mention that I’m white, had a crew-cut at the time, and was travelling reasonably well-dressed. Had I been black, Hispanic, Muslim, Sikh, or simply less well-kempt, I would not have liked my chances at avoiding a longer chat with immigration.

The bottom line is that they aren’t your friends. They don’t want to chat. They just want to screen out anything obviously unusual – and if you look unusual in any way then you can expect extra attention. Try not to be unusual.

I was in this exact situation when solo backpacking.

I don’t see any problem with honesty. The problem is, you’re agonising about explaining in excessive detail about how you’ll make your decisions, rather than simply answering the question.

Actual answer:

“I’ve got a business meeting, and then 6 weeks vacation from work, for tourism and to visit a few friends in New York and the East Coast [or wherever], returning home by about <date>. I might cut it short if my employer requires it, or the meeting doesn’t go as expected. Either way I expect to be back home to return to work, by about <date> at the latest.”

This is a simple straightforward way to explain everything they care about. If they have other questions, they will ask. Especially, it explains why you are visiting, your plans, that they are flexible, and shows that you are not planning to stay in the US and have strong ties (work, home) to the UK.

Incidentally, that last point is a crucial US immigration criterion, they need good confidence that you have strong ties back home, or aren’t planning to stay, to allow someone in, by law. So it’s worth including it.

They also get very few minutes for most visitors, to form that opinion, so keeping focused and to the point, on what they need to know, and evidence that backs it up available if needed (can you quickly name the company and contacts you’re meeting? Do you have emails or a hotel?) will help too.

If they have further questions, you can afford to be a bit vague on some of the finer detail. “Im definitely visiting X in New York, this is their address. But beyond that, I won’t know exactly until I get works reaction to the meeting. A lot hinges on how that goes, as to what I can fit in, and whether I will have to cut it short”.

A personal anecdote here. I had a very similar situation. I was staying for 3 days. If something was going well, 10 more days. I asked for 13 days. Provided all proof accordingly. Returned after 3 days.

For the US, the situation is even easier. No one will literally ask why you are returning early, as the US doesn’t have exit emigration checks and if you have a ticket and meet the entry requirements for your transit point and destination, the airline doesn’t care why you’re leaving.

If you do not want to say too much details, tell them the longer time that you are going to stay (6 weeks).

No worries if you return in two days. That is much better than say “two days” and stay 6 weeks.

The best way to approach this is to plan the trip that you would take if the meeting goes well. It doesn’t need to be a very specific plan, just “I’m going to this meeting and then I’m going to travel around for six weeks” plus whatever details you can provide. You can then mention “but I might have to cut the trip short if the meeting goes poorly,” but as you can see it doesn’t even look that bad if you leave that part out.

That sounds a lot better than the way you presented it in the question, and saying you’re planning to visit for two months and then actually staying for a week is far less problematic (as in, not at all) than saying you’re planning to visit for a week and then staying for two months.