My 4yr. old took 2-days adventure camp(2-days ski lesson)
exactly week ago.
At that time only Blackomb kids zone site was open.
They'd gathered kids at Whistler kids
school place and after took them to Blackomb by bus.
I'd recommend Blackomb side anyway. The learning field
for 3-4yrs group is placed within upper village(next
to Wizard express chair). So, after day of skiing you
come down there(say, around 1-2pm) with your camera/camcorder,
order your lunch in one of places in front of Wizard chair
and take a funny pics of first runs of your kid. Also, you might
leave the idea about skiing with your kid during the lesson time.
That is secured kids zone with moving carpet. If you've ever seen how 3-4yrs old are skiing you will understand.
At the end of the camp my son did not want to leave at all.
They have very good staff(most are Aussies, btw).