If you can, visit the KOA in San Diego. A lot of lessons there. We saw a mix of tents, cabins, church groups, small trailers, huge DPs, some ancient-looking RVs.
They have rental bicycles, pedal carts, a restaurant/snack bar, small store, pet areas, firewood sales, moveable fire rings, propane sales.
Another great one is the KOA near Mount Rushmore - horse stable, live bands, coffee shop, gift shop, etc.
Both of these locations had a lot of going on and they were a fun and festive operations. No hint of permanent residents. I have pulled in and right back out of many campgrounds with barrels of beer cans, makeshift porches, cars on blocks, old tires.
Matt B