A couple of thoughts:
1 - Lake Placid is a no-brainer. Easy drive, long in miles but mostly on the thruway. The town is fun for kids (and adults). The skiing is great; Whiteface and Gore both get Pres week crowds but much less than VT, and the setting is beautiful and has more "big mountain" feel because of the expanse of wilderness you see up there, without all the development clutter on other eastern slopes. WF has a rep as a tough cold hill but you can dress for it and there's plenty of intermediate skiing as well, especially compared to what you're used to further south. Gore on the other hand while further from LP has much more blue cruising terrain, definitely worth the longer drive. North Creek (town near Gore) unfortunately has much less to offer in non-skiing department than WF.
2 - drive / fly to Tremblant - not a bad idea.
3 - drive / fly to Quebec City, ski Mt Ste Anne and Le Massif. Big mountain feel, tons of blue cruising, and tremendous non-skiing setting - QC is the real deal, Tremblant base is an Intrawest development (Stratton on steroids). Long drive but it goes fast (again, a lot of fast freeway miles); get a good book on tape and it'll fly by. Travel time is not much different than hauling early to an airport, flying west, waiting for bags, waiting for rental car, checking in, etc. And it's a lot easier. And QC has more non-skiing activities than you possibly could cover - historic old city, museums, great food, foreigners talking funny, the Ice Hotel, tobaggon runs, etc. No US vacation crowds either.
4 - Stay in Burlington VT - great pedestrian city, good restaurants, movies, music, bookstores, giftshops and girl-friendly shopping, etc. Drive to Smuggs, Stowe, Sugarbush, MRG, Bolton Valley, etc. Easy JetBlue flight from JFK or a 5 - 6 hr. drive. We did a family trip to Mad River Valley last year and my girls (then 13 and 16) really loved the afternoon we took off to shop and eat in Burlington (the excuse was college visit at UVM but that was just an excuse). Also Ben & Jerry's factory nearby in Waterbury was a big hit with kids. Another option would be to stay at Bolton Valley which is central to all the bigger hills and the closest in to Burlington, you could probably drive in from there.
All things equal though Lake Placid is probably the most efficient way to get what you're after.