Pretty much everything that's been said is good info.
I've taken a trip to Summit the last week of March for 3 seasons now. When I skied Key I skied park pretty much exclusively, because the park is dope af. If you want to ski anything other than park go to A-Bay. The vibe there is right, the skiing is better, and overall its a damn good time.
Whatever you do avoid Breck at all costs, that place is a kook zoo.