As noted, the majority of campgrounds in New England close around Columbus Day weekend, however you will find a few that stay later. It would be unusual for the roads to be a problem. I lived in VT for 45 years and have seen many snowless Thanksgivings. Also, I have no clue where the 6 below statement comes in - fall temps may drop below freezing at night, but warm up during the day. With that said, there are always exceptions. It has snowed in October and it has gotten very cold as well.
Neil, Lin, and our furry companions, Ashby and Cody. 06 National Surf Side.