Not much to add to what Jeff said other than to say that Crested Butte Mountain Resort is currently at 151% of average snowpack, meaning they currently have 50% more snow on the ground than they usually do this time of year. Also, the snow isn’t done for the season. So expect a later than usual opening to some of the high elevation trails in Crested Butte. If you want to get up on the 401 I wouldn’t recommend going before mid-to-late July.
PS while there’s plenty of pedaling to be done in Whistler (so I’m told), if you’re not into riding lifts you’re really missing what Whistler is all about. Crested Butte has some lift access at the resort, but the bulk of the riding there is all about pedaling to the top.
Also, Jeff, not sure when the last time you were to Crested Butte was, but they’ve really been working on their kid-friendly offerings at the resort. Check out all this stuff, especially the mountain adventure program: http://www.skicb.com/content/summer-childrens-programs Climbing walls, bag jumps (had to do that myself), zip lines, and more. That said, it’s still a pretty small town.
I’ve never ridden in Crested Butte, but I have been to Whistler a few times. It is Disneyland for mountain bikers. The first time I went, I brought all my trail riding stuff because I too thought, “I’m not that into DH.” Well after one day in the park, I changed my tune. My trail stuff stayed in my suitcase for the rest of the trip.
There are some fun trails around Lost Lake which is adjacent to the village, but it’s more of a pre/post work ride kind of place. The valley has shit tons of other trails too, but again, I spent most of my time there in the bike park.
Squamish, which is on the way to Whistler has some incredible singletrack. There’s everything from flow trails to uber tech.