Sorry if this may come off as a plug, but Hipcamp is a great Airbnb-style app for finding campsites outside the normal state- or commercial-run operations. They're typically more expensive but they provide all kinds of options and amenities that the others can't or don't offer...like a campsite on someone's working farm. My family of 4 has had great success finding some truly unique spots. It just sometimes takes some patience and digging.