Hwy. 99 from Whistler to its terminus at Hwy. 97 near Cache Creek passes through some very mountainous terrain and provides access to fine scrambling and mountaineering, as well as rock climbing and bouldering. Marquee alpine areas include Wedge Mountain and the Joffre group, and there's rock and bouldering to be had near Pemberton.
The summer alpine season is quite short, often limited to August and September, but winter mountaineering and great backcountry skiing can be had. Locals, local shops, and at least four guidebooks provide good information.
Some, but by no means all of the rock climbing in the area is covers in McLane's Whistler Rock Climbs guide.
Getting There
When you're in Whister, Hwy. 99 is hard to miss. Drive north.