I recommend riding the #99, head towards Pemberton and head north to Lillooet. It is a beautiful ride fallowing a valley and canyon. Some twisties but easy riding and the speed is slow. Early start is best and have lunch in Lillooet then back track to Whistler. Well worth it.
If you wish to make a longer day you can loop around back to Vancouver.
Once in Lillooet head south to Lytton fallowing the Fraser canyon to Hope, then west on #7 back into Vancouver.
The downfall of that is you will be riding into heavy city traffic once back to the Vancouver area.
The best way once on #7 after Hope is to stay on it till the town of Maple Ridge then cross the Golden Ears bridge to get back on the #1 transcanada. Head west on #1 to North Vancouver to head back to Whistler.
You could ride this in the opposite direction with an early start and avoid the majority of the mad traffic, so ride east to Hope, #1, #7, to Hope, north Fraser Canyon and so on. It will take all day but breath taking scenery.
Have fun ride safe.