I think you’ve gotten some good recommendations so far. Another school he might want to look at is Utah State which is quite close to skiing (at least in looking at a Yelp map of skiing in the area) and which I think your son would be extremely likely to be admitted.
Although your son wants to head west, I’d still think it’d be worth applying to UNH and UVT in case he changes his mind during his senior year and would prefer to stay closer to home.