Throw on some layers, boots and gortex so you can check out some of the shoulder season adventures that await exploration. Down at Cheakamus Crossing and Function Junction are several trails to explore. Train Wreck is shorter and wildly popular. The remnants of boxcars that derailed back in the 1950's and are now surrounded by forest. The painting is ever changing so regular visits are a good idea.
The Interpretive forest has a variety of trails. You could spend an hour or up to a day wandering this multi-use trail system. Most common is up one side of the river, cross the suspension bridge and down the other for a pleasant hour. Driving a little further up the forest service road and Cheakamus Lake awaits. You may have seen the glacier blue waters from Piccolo or Flute when you're up skiing Whistler.
Up at the north end of the valley is Cougar Mountain and the Ancient Cedars. Take plenty of time and enjoy exploring these mammoth trees in their mossy surrounds. Kids will be occupied for hours climbing over some of the fallen giants.
Before you know it, there'll be snow on the ground!