I think the Hudson River Valley and Catskills region to the north of NYC might suit just nicely, Beverly. Not sure exactly where you're based in New Jersey, but it's probably a little under three hours to get to many of the area's historic resorts and lodges; places like the venerable Mohonk Mountain House, one of America's oldest family-run resorts and an ideal spot for a memorable Christmas get-together. Another slightly cheaper option might be Rocking Horse Ranch in Highland, NY, which has its own Winter Fun Park with sleigh rides, tubing, ice-skating, and some easy downhill slopes if any in your group want to give skiing a go. Rocking Horse also has a small year-round water park with slides and fountains for your grandson to enjoy. Up the road in the Catskills, maybe try the Emerson Resort & Spa or Hudson Valley Resort & Spa for top-class lodging as well as spa treatments. Pinegrove Ranch and Family Resort is another popular family choice, offering a range if fun winter activities including free ski lessons and equipment rentals. More info about things to see and do around the Catskills, plus places to stay at this link: http://www.visitthecatskills.com. Meanwhile, in the opposite direction and not quite as snow-centric, you might also look into a stay at Pennsylvania's Hershey Lodge, a very festive (and chocolate-y) flavored choice with things to do for everyone in your group (including a spa and access to Hersheypark and its host of holiday-themed events and entertainment).