It s really too big to see in just one day, you ll end up riding lifts all day
Vail is pretty centralized for the most part. You could go to Lionshead first because that is where the gondola is, and I think that there is tubing on top of the gondola at night. They have ski biking at night down the mountain. You could also go to Beaver Creek down the road about 15 miles, but that is a bit more touristy and not really outdoorsy, but they have a nice skating rink in the village. Vail has some of the best back bowls to ski, and the views from them are amazing. Hope you have fun!!