This tread is great - lots of great advice / info. Try not to get locked into any membership. Most membership campgrounds are now allowing the public and offer yearly memberships (Thousand Trails) and are all about keeping the corporate hierarchy wealthy.
We learned the hard way and now feel locked in. The reason we joined one (Thousand Trails) was because we loved what they consider our home park. Enjoyed it for multiple years thinking we would eventually break even at some point. The park now has a fraction of the transient sites (converted to permanent) they had when we joined and is allowing the public in. So they have succeeded in the objective of keeping the campground full and generating lots of income from the permanent sites…while the long time members are scratching our heads thinking “what happened?”