>But wouldn't that lead to people living in the middle of nowhere where there aren't many jobs?
In theory, no. A UBI is not a free pass for a luxurious lifestyle, it's a basic income. If you want more than that, you'll have to work. If you want to not work at all and sit on your ass, then sure, you can go move to Tornado Alley or frigid Minot or wherever and live cheap and make some extra cash doing odd jobs like shoveling snow maybe, and smoke pot most of the time. I don't think most people want to live that way; people are too greedy for that, and want a nicer standard of living than the bare minimum. So, people will strike a balance, like they already do: they'll look for places that are affordable, but where jobs are also located. But unlike now, they won't feel so much pressure to live where jobs are, and might take a chance moving somewhere cheaper. We'll probably see more movement to lower-cost, smaller cities, and maybe some revitalization of small towns, but overall I don't think it'll be all that huge. I would expect a lot of people to move out of the really high-rent places where they're being subsidized by government programs to stay there.
>also what happens to all the people living in projects in what would otherwise be expensive areas? Ship them off to a sparsely populated non desirable area? Good luck with that
Why not? If they can't pay the rent, they'll be evicted. Then they'll have nothing but the clothes on their backs, and their UBI check, so if they want to have a roof over their head, they'll get a bus ticket to someplace cheap. This is a good thing: they're not contributing productively to their current city of residence, and instead of draining it of taxpayer funds, and they're taking up space that could be used for more economically productive residents. If their labor is really needed there, then the business owners need to raise their wages to allow them to afford the rent there, otherwise the businesses can go under. If the place is so high-rent that all the businesses move out and all the service workers move out, no problem, it'll collapse under its own weight and then after the landlords all go bankrupt the rents will go back to sustainable levels. Trying to keep people like that in an area isn't doing anyone any favors, except those who are profiting from the situation.