Small towns can be a good choice as Gary Haupt suggested.
I live near a town of about 1500. Three or four years ago I was at the gas station about 8pm and a couple in a Class C pulled in. They asked if there was someplace they could camp for the night. I knew the park had let people camp in the past, but the maintenance guy who collected money ($7 a night with 30A and access to a drinking water hydrant!) and gave permission had retired. I called our sheriff's department and asked if the town marshall was on duty. When they asked why, I explained, and 2 minutes later he pulled up in his police vehicle wearing shorts, a T-shirt and flip-flops. He gave them his card and told them where to park and if anybody questioned them to tell them he said it was okay.
Doesn't hurt to ask.