Skied the area about twenty years ago and loved the place, especially Breckenridge.
If hiring a car/bike get one with a big engine: We had a cheap small 2-litre dodge (Chrysler) neon, it was down to 20mph in 1st gear going through a summit tunnel with my foot to the floor. One of us got altitude sickness and hardly slept for two weeks, I had nausea and headaches for a few days.