So many good options. Here are a few.
Pedal out to function junction. Riverside, high line, road to climb babylon by bike, down see colours and puke, into high side (will be dusty). Down riverside, cross over suspension bridge. Up to loggers lake, down ridge. Then if you feel good go ride train wreck. Some of this is on the route for the enduro race here http://www.worca.com/events/sea-sky-enduro-series-4-whistler-valley-cheakapotamus/
Lower sproat, piece of cake, a-la-mode. For a bit more challenge with some rock rolls go down three birds turn right and back up a-la-mode. Continue on lower sproat, up road to go down Danimal North, up whip me snip me, down lower beaver pass, bob's rebob, get over it, down mel's into emerald forest.
Great views but a more challenging trail is up the flank to Howler. Might not be the best on a 5" XC bike though.
Yummy numby, reverse along comfortably numb, down jeff's trail to sea to sky. If you want you can head out to parkhurst to see the ghost town and back to finish at lost lake. Alternate is take foreplay (end of comfortably numb) after yummy numby, but it's a little rockier.
Get the whistler trail maps app for iPhone/android or the following site http://trailcheck.in