Liberty isn't open yet, because there isn't enough snow/it's been too warm. But if you're planning ahead, it's the closest/easiest, but does get crowded.
My kids and DH are into snowboarding, and they really enjoyed going to Seven Corners, which is not too far and is kind of an old-timer's resort, with activities. Poconos is another good option, but check for conditions, because climate change hasn't been good for ski areas.
This weekend my family are driving up to Mt. Snow in Vermont, which is not a short drive, but they are chasing good slopes.
DH is a big believer in buying your own equipment rather than renting. Rentals tend to be poorly fitted and poor quality (ever rented ice skates at local rinks? you'll know how uncomfortable those are). He first got their gear on Craigslist, but now that they are really into it and have the Epic Pass, he bought new boards for everyone. It just makes the snowboarding so much more enjoyable when you have good equipment.
Keeping track of everyone's clothing is kind of a nightmare (thermal layer, long socks, ski bib, ski jacket, gloves, helmet, goggles), but if your family really get into it, it'll be worth the hassle.
Sadly, I'm not interested myself, which makes me feel left out, but I know they are having fun.