COE campgrounds anytime we can. Most prevalent in the south. Rates for us old folks are about $9-$11 a night at 50% off, and the sites are wooded and huge usually. Not so many of these the further west or northeast you go, though. We have a book "COE Campgrounds of America" which is helpful. Our state parks are 25% off for seniors, but some states I've seen don't give any discounts to non-residents.
Just from observing while driving down the road, I'm disappointed in a lot of private campgrounds. Here, anyone with a pasture can put one up. I took a 38 mile drive yesterday and passed 9 separate places where you can park an RV. Most are just people's 5 acre house sites........but all have RV's in 'em!!! Can't remember the last time I saw an empty RV Park, public or private, anywhere..........
"Next to prayer, fishing is the most personal relationship of man"Calvin Coolidge
"American by Birth, Southern by the Grace of God"Lewis Grizzard
2016 GMC Denali 3500Dually--2017 CC 36CKTS