I think that gottalovem put it well. Although I don't know where you are currently living, so it's difficult for me to know whether you are moving an hour away by car, or if it will be a plane ride.
I tend to agree that if you are feeling that this is the right thing for you in your life now, it may be time to distance yourself from difficult child's day to day living needs. If she is still financially dependent upon you and having her come with you is part of that, then maybe you need to reconsider. Even if you would want it, she can not live with you forever. There will have to come a time that she needs her own place and her own life. It's better that she figures it out now with your help than later on when you can't help her.
Is she eligible for assistance of any form that would help her with getting her own home? Maybe a church program or a Goodwill type program? There are options out there if you know where to ask.