We stopped at the Lee Hi Travel Plaza/RV Park near Lexington, VA, on US 11 at Exit 195 on I-81. I heartily DON'T recommend it. The RV spaces were on a hill about 50 feet above the truck parking. Several trucks and refrigerated trailers ran all night. You may was well boondock in a truck stop for free.
During the same trip we stopped at Norrie State Park, NY. Sites were all dry camping. It was okay as a park, but the draw to me was being close to Old Rhinebeck Aerodrome. Try to go to Old Rhinebeck during their air show. If not, their museum is pretty good.
These may or may not be near your route:
We also stayed at Bar Harbor Campground, ME. It was a very nice place to camp. The riverside sites were cramped and sold out, but the interior ones were private. Some had full hookups, some only water and electricity.
Camden Hills State Park was nice, but I don't think we had any hookups. There may be some sites with hookups.
Salisbury State Park, MA, was nice. It's right on the river and ocean, so it may fill up.
Hickory Run State Park, White Haven, PA, was secluded, with no hookups.