As a local who's been to whistler more than a few times, I can say you guys are absolutely right. The section from Vancouver to Whistler would be suicidal by bike. Mostly single lanes (you get the occasional double lanes for passing, but those are only for 1-2kms or so), and narrow. And tons of sharp curves.
Side note: yep, lots of construction going on. they're widening and adding lanes for the 2010 Olympics.