We moved 200 miles from my daughter and 3 grandchildren 4 years ago. At the time when we spoke about what our plans were, they were all in favour of it. However, once the deed was done, it proved to be a whole different story! We thought in this day of excellent communications, emails, mobile phones, video calls, etc. that there wouldn't be a problem. However, she says now that she only said what she thought I wanted to hear at the time, and has made life and communication between us extremely difficult ever since! She claims to have told my husband, her stepfather, that she really didn't want us to go, prior to the move, but I have severe doubts about this, one because I don't believe my husband would lie to me about something so important, and two, because at 36, being very outspoken at the best of times, and being very close emotionally, I think it highly likely that if she hated the idea, she would have told ME!
I also thought that my granddaughters, who I was very close to, would want to come and stay in the holidays and would frequently FaceTime with me, and that we could maintain a good relationship this way, but again, this wasn't to be! My daughter keeps coming up with excuses as to why they can't (read won't) visit, so any visiting that is done, is done by us, and as one of the main reasons we made the move was because my health is bad and my husband needed to give up work to care for me, I find it really hard to do the journey, but will continue for as long as I can.
I recently talked to her about the possibility of us moving back, and she made it clear that even if we did, she would only see us on her terms, and as and when it suits her, leaving us, twiddling our thumbs, living a life we don't want to, in a place we don't want to be, and short of money into the bargain, while waiting on our family in the hope they'll spare a few minutes to call in.
I guess what I'm trying to say is, do it, because it's the only time in your life that you're going to get the opportunity now. You've given your children and grandchildren support and are willing to continue to do so, but just in a different way. So while I do feel for your daughter, she has to be made to realise that now is YOUR time, and it's probably a case of now or never. As a previous poster said, maybe ask her how she would feel if you made it clear you didn't want her to live her life in the way she wanted, and made life unpleasant because of it. I do hope she doesn't prove to be as selfish as my daughter has become.
Good luck with the move, and I wish you a wonderful new life wherever YOU chose to be!