Welcome to the forum Het.
Whistler / Blackcomb is an awesome ski area, great village, no need to have a car and travel anywhere else. However, the weather there is unpredictable, and can certainly ruin a ski vacation. I've been there twice, actually once in the winter, and it was terrible. A lot of snow quantity, but terrible quality. Fog, wind, blowing snow, no visibility, not very pleasant to ski in. And yes, huge crowds. Just about everyone of my friends who have been there has had the same experience. Actually, I know few people who will go back.
My advice is to go to the Lake Tahoe area. Many huge ski areas to choose from. Squaw Valley has all the SUPER steeps and bump runs you could ever dream of. Alpine Meadows, Heavenly, North Star, Kirkwood, the list is endless. This area is truley a skiers paradise. The weather is MUCH better than Whistler, sunny California compared to foggy BC.
Your best bet is to rent, (hire) a car. Can you drive on the right side? There are a lot of hotels in the area, but most are a short drive to the ski areas. There are rooms at the ski areas, but you will want to ski more than one. I'm not too sure about public transportation out there, others on this forum can answer that.
Good luck, and have a blast wherever you choose!