NY, that sounds exactly like what happened to me recently. The person involoved lives 1 hour+ away, one way. So I went up there, explained how the bees work and their friend who works for a honey manufacturer calls them and says "put some lemon grass oil out, they'll come out of the wall." I told them that wouldn't work, but hey, it's their house, go ahead and try it. Two weeks later they call me back, guess what? The bees are still in the wall. So I make a 2nd trip up there and start doing more recon, probably about 2 hours that time around crawling all around their house, and tell them what my thoughts are and what's involved. I thought I was starting that afternoon, but he tells me he wanted me to come back the next night, it'd be more convenient. I go back the 3rd time and we run into an issue, tho not a big one, the bees are in the soffit, not the wall and since the house is stucco, I don't want to cut it. He decides he wants to call his contractor out to pick his brain about the situation. Ok, sure, fine. A 4th trip up there and another couple of hours with the home owner and the contractor. The contractor says "I had bees going in my house under my tub, a beekeeper came and had like 98% of them out of the wall in a few hours using queen pheromones, and didn't have to cut into my house at all, why can't you do that?" Once again I explained it doesn't work like that. The contractor again says that this other beek did it, but agrees, don't cut into the stucco. I told them then call the other beekeeper and get him over here, cause I'd like to talk to him and see what his secret is, it's not possible. The home owner again looks at me like he is still doubting me, but wants to know if there are any other options. I told him a trap out is the last option. He asked me about doing a trap out, of which I told him being a 2nd story roof soffit would be a bit of a pain, take a couple months with constant supervision (more trips) to do and your going to leave the comb and honey all behind which will melt in the summer heat, then explained the problems that they could have with that too. He then tells me that he wants to explore other options.
Fast forwards another 40 days or so and now I guess their other options didn't pan out, so now they want to know "when can you come up and get started?" I don't mean to sound rude or anything, but I already have over 10 hours invested in this venture, prob out $100 in fuel so far so I am a little put off by their "just drop everything and deal with my problem now that we agree with you" attitude now that they realize what I said was right. Plus now that the colony has been there for 2 months+, I'm sure it's a lot bigger. I have other people that have problems with bees too that I am currently dealing with , I have not been home for a weekend in 3 months, so I am to the point that they are last on the list. What the saying, "Lack of planning on your part does not constitute and emergency on my part"?
So if anyone wants a job, let me know, they can have this one. I'll just watch from a far.

opcorn:
But to address your question about how late? I did one last Nov 2nd and they made it thru the winter just fine. In fact, that colony is one of my top producers this year, they have just about completed filling their 2nd deep super.
C2