At Whistler ride a gondola up to the alpine if its a nice day and the town site to explore if you like that. There is a fun gondola ride called peak to peak between Whistler and Blackcomb. Not for those who don't like heights.
An alternative is go on to Squamish as mentioned. There is also a gondola for an easy ride upto the high country, trail, views and a restaurant.
The on 99 is steep but slow and easy will do it. If you are leery of the hill and not to take it and decide on hwy one to the ferry at Horseshoe Bay instead continue on to Britannia Beach as mentioned or Squamish. Kind of far into Whistler and back for your schedule.