I think it is sort of a personal choice; a lot of it based on your relationship. If you weren't living together before, do you think your ready to progress to that now, or would you be doing it more out of convenience? I think part of it also might have to do with what stage of addiction he was in, how he is doing in recovery as that will give you an idea of how stable he will be when he comes out. My husband came home right after a 3 month rehab and there were ups and downs, but we handled it all ok; also used therapy and some marriage counseling. So I don't put much stock in a generic one year rule; but that's just my experience.
Does he know for sure he will be able to find employment in Prescott, obtain a place to live, and how will you work out all the details - something to think about in advance maybe. And great about your schooling - sounds like it would almost fast track that for you; no waitlist.
We are from Arizona also. I had looked at rehabs in that area; and your right there are a lot there & I think they say its like the rehab capital of all the western states or something like that. My husband ended up going to one in California, but it was really tempting to pick one in-state for convenience.
I hope you have a little time to think about it; Id say just keep trying to look at it from as many angles as possible and that will hopefully help with the decision.