I happened across Sesquincentenial State Park. Ooooooooh, lovely lake.
Stayed the night for $16. I met Cliff, the "host." The parks hire retirees and such to live in the park in their RV's for a month or so at a time, and Cliff, from Michigan, was this campground's host.
The campground was a very American thing, with the mix of wonder and disdain implied by that term when its used by an east coast urbanite or European. There are 50 or so "sites"; parking spots paved with hardpack, splayed around a cul-de-sac, and each furnished with a bollard sporting electrical outlets and a water spigot. There is a central heated building, with clean toilets and hot showers, and there are picnic tables and fire pits. Metal signage on perforated posts gives rules and notes the handicap accessible site. The only way you know you are in the woods is by all the trees.