Interesting, you think you'd get bored at a huge place like Big Sky and you ski REGULARLY that tiny little hillock called Hunter !
Its amazing most folks would say Windham is better than Hunter because the crowds are slightly thinner but both mountains are pretty terrible, in my view, some of the slopes are ok, but the lift system at Windham..its I daresay bordering on unsafe, the waiting markers are actually camouflaged, am being sarcastic! Frankly, Windham is probably the worst place I have ever skied, and almost everyone to the man or woman told me, if I hated windham, hunter is worse (note went on holiday weeked!! hear hunter and windham during the week are a lot better but generally just didnt think much of the slopes at Windham)Anyway to your original question: seriously speaking,
I researched spring skiing (OP did not mention when they plan to go so this is my assumption) and taking into account your boys are expert skiers, these are the best deals if one is not looking for the absolute least cost which comes at the price of major inconvenience, i.e. staying far from the slopes, major driving etc, the most economic deals for on-mountain or as good as ski-in/ski-out I found were at the following places,:
1. Big White Canada
(if you can get to Toronto, the cost includes the flight from Toronto to Kelowna, BC and the shuttle into and return all the way to Toronto) and that price is in Canadian dollars..the entire village is ski-in/ski-out
2. Snowbird, Utah,
the deals there are pretty serious
3. Mammoth Mountain, California
- again totally in base village so ski-in/ski-out or ski in/ but walk to ski out. the pricing was really good.
4. Big Sky, Montana
- you mentioned this and note of all the 4 places mentioned till now, of course the caveat being its the worst travel routing from the Eastern seaboard. I am not sure a mountain like Big Sky can be skied in a week or for that matter if you include Moonlight Basin, forget it..
5. I have not looked into it but almost certain Whistler
has probably the best deals on the planet, and that is a big mountain on an European scale.