OK, I know you this is a PA page, but I'm wondering if you might try closer to home -- namely Snowshoe Mountain Resort in WV. This four-season mountain resort offers a slew of fun off-piste activities including boating and fishing on Shavers Lake. There's also a top-notch mountain-bike park here if your 11-year-old fancies trying some downhill biking. Nearby in action-packed Pocahontas County, you've also got attractions like the Cass Scenic Railroad and easy-grade biking along the Greenbrier River rail-trail. The resort is currently offering some activity-focused package deals that might suit your itinerary, too.