I spend 1 month in Vail every summer. Use Colorado Mountain Express to & from Eagle/Vail airport. Cost last summer was $45 pp, one way. They take you right to your condo or hotel door. I would make a reservation on line or via 800 number since it's ski season. Rate could be higher during ski season. I've been using them for 20 years.
Some of the restaurants that are open in winter are closed in summer. Best restaurant for dinner is Sweet Basil. There are many others. If you want more casual Red Lion is good. Music on their porch/bar. Creekside Cafe has good food. Lots of people go to Blu's. I don't think their food is that good and staff has an aloof attitude. If you see any names that look good, you can PM me or email me & I can tell you if I've had experience with them. One thing I know for sure - BRING MONEY! Tourism was way down last summer and they were very worried about what winter would bring.
I don't know anything about Avon or Beaver Creek. Just Vail & Lionshead.