I did a little mt. biking in Whistler a few years back while driving through en route to Alaska. We parked at the base of the mt. and rode the trails just back from the parking lot. We only rode for a couple of hours and found trails that were fairly easy- there are fire road and single track trails there. The single track is not necessarily hard but tends to be full of tree roots (typical of a boreal forest) so there was plenty of throwing weight around to get over them. It is a fun and beautiful place to ride though.