Headed for the Mountains
Join Date: Jun 2006
Location: Vancouver, BC, Canada.
when you are carrying a kid, you are looking at getting the most bang for your buck, or in this case, the most spectacular trail for the least effort. My wife and I did the High Note carrying our 1-year-old and would recommend it greatly. Try for a weekday (less busy). There is a bail-out point called the Half-Note Trail. (I love my wife dearly, but I should not have told her about that bail-out! The kid was fine.) They won't let you take your kid up the Peak Chair, so expect a 1,000ft elevation gain hike up to the start of the High Note, as a warmup.
You mention the cost: Find a coupon for the gondola before you get to whistler. (7-eleven? or Entertainment book?)
Garibaldi Lake and Elfin are both great suggestions, and more "in nature" but with a lower view-to-effort ratio. (Garibaldi, think +3hours of hiking one way before reaching the lake.) If you bail after 2 hrs, you have a 4 hr day without the view--still nice, but not the big payoff.
You have a car: I also very much enjoy the High Falls Creek trail in Squamish (search this site). Think 2000ft elev gain and 10kms which are both within your limits.