Skied there about 10 years back and really enjoyed it (two weeks in Breckenridge but visited Keystone twice, as well as Vail x3 , Beaver Creek x2, A-basin) so it must have been OK. I remember it being quite linear, basically three mountains one after the other with the best stuff (i.e. most powder stashes) at the back. I can't rememeber how long it took to get to the back but it's not a big European style area so I'd imagine its about 25-30 mins if you made a bee-line. As ever with skiing in the US things just work and the food's good and reasonably priced. Enjoy it.
And remember you're at altitude so if you ski as soon as you get there don't try and take on the world – loads of water and less beer. And if you go up to A-basin it's really high and if you're in powder it will knock your t**s off if you don't consider the effort involved.
Enjoy it you lucky git 😉