We spent 3 months traveling outstate NY and New England in the summer of 2016
These parks were nice. Not sure if it's where you are going though.
In Queechee Vermont.
Pine Valley/Quechee KOA 802-296-6711
3700 Woodstock Rd, White River Junction, VT
Reasonably priced for a KOA and a delightful place. Owners are awesome, and the campground is always full. Don't get a place up on the hill.
Lake Winnipesaukee area of NH
Turtle Kraal RV Park 603-855-2377
14 Fox Trot Loop Alton, NH
Nice big sites, great management..gated.
Campobello Island area (way north)
Sunset Point RV Park 207-733-2272
37 Sunset Point Rd
Lubec, ME
Nice sites right on Johnson Bay
Right across the border from Campobello Island in New Brusnwick (Roosevelt's summer home)
Quaint little town, a few really good restaurants
In the Bar Harbor area of Maine
Narrows Too Camping Resort
Rte 3
Trenton, ME
About 5 miles from Acadia NP and 20 miles to Bar Harbor
Big pull through sites...great wifi
We were traveling in July, August, September...lots of lobster stuff going on in August.