I know a lot of users are posting on here about resenting their parents for moving, but I'm going to be controversial and post the opposite
I'm 20 years old, currently about to go into my third year of university (don't ask why I'm on mumsnet, it's strangely addictive...). My uni is about a 4 hour drive/3 hour train journey from my parents home, so I normally only visit home for a long weekend in reading week and in the main holidays. Hopefully I can give you an answer from your kids perspective!
My parents decided this summer that they wanted to move. It's something they've been talking about for years, but last month they found a house and fell in love with it. There were a few complications with buying it/selling ours, but it luckily all went through. I know my mum would have been heartbroken if she didn't get it, it's really her dream home. They're both really excited, and moving 2nd week of sept.
Here's the catch- I'm going into my third year of uni, but I've chosen to do it on a study exchange. I'm leaving in september to go a different continent (!) to study for a year. This means that not only am I leaving the country, but I'm leaving the house I grew up in forever. I won't see the new house for a year. It's a weird feeling, but I absolutely don't resent my parents in any way shape or form. If anything, I'd feel even guiltier knowing that my parents have given up something they wanted so much to keep me happy.
Obviously it hasn't happened yet, so there is a chance that my feelings will different when it actually happens, but I doubt it. I'm an adult. Your children are adults. If they want to see their home town/friends, they can visit for a weekend. There's always going to be a connection with your childhood home, but it's going to be sad at any age (my dad was moody as hell when my grandparents sold their home, and he was mid-forties!)
also, have you actually spoken to your dc about this? Or are you just assuming they'll be unhappy in your new place? Please give us young people a bit more credit- we're a lot more mature/less selfish than you think!
hope I helped (and sorry for the long post!)