Where is this? It sounds like one we used to belong to in WA but didn't pay anywhere near that. Many of their parks are rundown and/or overcrowded in the summer and you have to book way in advance to ensure you get a site. Not worth spending $8K on something like that. Some of the membership CG places are like dealing with a used car lot and will take advantage of you every way they can.
Look into buying a used membership in a CG network. We bought a top of the line Thousand Trails membership for $800 off CL and can use any of their CGs across the US for no extra charge per night. If you do some googling, there is a blog or website that explains all about buying a pre-owned membership. As far as Thousand Trails goes, if you talk to a seller, get their membership no. and phone head office to see exactly what the features and benefits of the particular contract are because they can vary quite a bit. Sometime you may find there's a lot of back-dues owing.
If it's a membership CG network, the sites are first come, first serve.