We paid a lot of money for our Coast to Coast membership.... and it seemed no matter when we wished to stay there or what area or state....they NEVER had room. We had several "sister parks" we were supposed to be able to stay at....but that never worked out. They were quite heart-broken as they proceeded to tell us NO.... We saw a lot of crocodile tears at those parks!! 
Through the years, we have talked to very few who were pleased with the membership campgrounds.. We did rarely run into someone who had good luck with them...but I'm telling you it was as rare as finding a hen with teeth..
Save your money and shop around for the 50% off club parks such as Passport America. Or use your RV travel park books and find those "mom and pop" places that are reasonable in price, but offer many amenities and a lot of bang for your buck.
I highly recommend State and National parks too! Corps of Engineer (COE) parks are good as well. There are many places to stay that are reasonable.
Good luck and happy travels!
Joella