whis and blackcomb together are huge (not europe huge). every one likes something different there but, you can cover both resorts in one day as a recon mission if youre really dedicated and really fast.
my day in bounds at whis with good visibility usually starts early am on creekside gondy, go all the way up. blast over to harmony, go up, down into sun bowl and over to symphony. lap sympthony until lots of peeps get there, then start working your back over the ridge. peak express offers gnarly lines (my favorite is west cirque, but go whistler bowl to get a feel for em first), i would lap them until about lunch. take peak to creek non stop and eat something in the village. peak to creek is a leg burner!
then in the pm go excalibur, excalibur, glacier, showcase tbar, hike up and do blackcomb glacier. the first time around just go down the bowl, but you can find some sweet lines up the sides. ride down horstman to chill out, then go up jersey cream, ride over to 7th heaven and have a beer in the hut. ride that area until close.
you sort of follow the path of the sun throught out the day so that snow gets a chance to soften up a bit.
if vis is bad, there are so many nooks and crannies in the trees on blackcomb. literally too many to make note of. if you see tracks going off the main trails, likely its a good spot.
if you get tired of the resort after day 3, i would get daymakers + skins and a guided tour through some BC. from my experience, ive always been happier riding cowboy ridge than anything else in bounds.
ive only spent about a month there, id still consider myself a tourist.