Better ways than CME....DD- How many are in your traveling group? If its 2 or more, you are better off renting a car than taking CME. You will save $$$ and gain flexibility.
CME charges about $65 per person, each way from DIA to Vail. And at busy times, they can add an additional hr to what should be barely a 2 hr drive. It comes from wait time, and dropping off others enroute to your drop off. And on the way back to Denver, you may be picked up an hr before you actually leave Vail.
A car rental for a week runs as cheaply as $125, and provides you with the opportunity to move on your schedule, not theirs. And should you wish to hit Summit Cty areas (Breck, Keystone, Copper, Loveland), you'll be very glad to have the car, since there is no public transportation between Vail and Summit Cty.
Even if you leave the car sit at your accomodation the entire week, it's still cheaper and more efficient than CME.
By the way, there are also other vans services to Vail.