I would say Salt Lake City, Utah is probably the best place to train if you want to get serious. I've never been to Whistler, but it seems like it would be mad expensive up there compared to Utah, plus you have to deal with immigration to Canada.
There are like 8 Mountains that are half an hour away from Salt Lake city and they are all DOPE as HELL. If you get sick of the park at Park City, hit up Solitude on a powder day and you will be in Heaven. Snowbird is fucking sick too.
All of the other places you listed are kind of weak compared to SLC in my opinion as far as having a HUGE variety of different places to go if you get tired of one mountain.
But if you want to come to Montana, I got a place for you to stay. :)
Ron Paul '08
New Skate edit from Seventh Skatepark, MT
Buy Destructo, Adidas, Satori, Creation if you skateboard, the quality of their product is ridiculously dope.
An old friend of RP compared this campaign to the tortoise, and our opponents to the hare, in the old Aesopís fable. The hare was fast and flashy, but because of over-confidence and carelessness, he lost the race.