Are you going to take the coastal route the entire way up? If you do, you might be a little pressed for time. I drove from Vernon, BC to Newport, OR and back in 10 days and that was a great road-trip! I would suggest taking the ferry from Ana cortez into Victoria and spending time there, then you could ferry to Horseshoe bay on your way to Whistler. Since you're on the island it would be great to check out Tofino and Ucluelet but you might not have enough time.