There are a lot of parks, and most are either free or almost free. But as I remember when I lived in New England, when my father and I went cross-country skiing a few times, and there were others out there as well, just not that many.
My mother attempted to go cross-country skiing on a golf course, and was chased off by security. Would think a golf course would be a perfect place, but turned out not to be.
Most people preferred downhill skiing. Just the way it is, I guess.