Might also be worth looking at a few of these: Lake George area (Lake George RV park and/or Moose something or other); Watkins Glen; Bush Kill Falls Areas/Delaware Water Gap KOA; Lake in Wood, Lancaster, PA; Gettysburg KOA, Drummerboy or Artillery Ridge; Harper's Ferry KOA; Castaways (Ocean City, MD) and Massey's Landing (DE) - though both are pricey for cabins; Trap Pond State Park (I believe they have cabins); PA Grand Canyon Area (I can't remember campground names, but most have cabins); Ohiopyle, PA area - there is a Jellystone there w/ cabins....
We really liked Luray, VA's Jellystone - that's about 5 hours. Also loved a small campground near WV - Candy Hill, but can't recall if they have cabins. Cherrystone and Bethpage are awesome, but cabins won't be cheap.
ETA - there is a new campground at the inlet bridge in Delaware - that might be worth checking - I believe it's a state park, but not sure about cabins. Assateague National Park is also awesome, but not sure about cabins.
