I'd consider renting a van through Vanture Customs. We're Philly-area too and rented "The Wanderer" for our Cherry Springs trip. We're campers anyway but considering what the weather could be like in March, a van gives you the ability to stay close by but sleep warm too. I believe Ole Bull is open year round and it's not too far from Cherry Springs.

The only other consideration is the combo of distance and luck of clear skies. We're 4 hours away, and while we consider it absolutely worth the drive, we try to do at least an extended weekend. We've gone and had only 1 good night to view stars, and we had a trip with no clear nights. Giving yourself an extra night or two, if you're able, is worth it in my opinion!