I was in Grand Junction a few months back, shuttles and some XC, and ran into a couple from British Columbia. They were here mostly for the single track. They were checking out Moab and shuttled with us in Grand Junction too. But they were not here for the lifts, although they were going to check them out for a day or two.
They said there are lots of little places with lifts/shuttle service in the NW that are awesome. They said Whistler by far has more trails, and some great ones, but there are more to check out.
If you want to check out CO then by all means do. There are 4 resorts that offer lift riding. Keystone, Winter Park, Sol Vista and Vail. 2 days at each, with a few days off for breaks, could easily fill up 2 weeks.
Crested Butte and Snowmass also run lifts but don't have many trails. So bring a XC bike and check out that aspect of those areas. Its not CO, but Angel Fire down in NM has some awesome lift access DH.