I'm in the same boat. East coast rider on my first trip out west at the end of February. We booked our tickets not knowing it was the same week as Vail is hosting the Burton US Open.
I work with someone who has been out there and he advised me to skip Breck and Keystone(unless we're gonna take the cats) and just go to Vail and BC. He also said I-70 gets a ton of traffic in the morning and we should leave extremely early if we're coming from right outside Denver (we'll be in Aspen Park).
I saw a previous post on here about free parking, do you have to pay for parking at some of the Vail Resorts mountains!?
What week you heading there I arrive in co on the 28th.