Heres where we like to go it Land Between The Lakes...Its $25.00 a year for back country pass per adult kids are free.Stay on one site up to 14 days.But you just have to go to another site which theres plenty of.They was going to up the days to stay not sure if they did tho. Heres the site
http://www.lbl.org/
We now buy seasonal sites which runs anywhere between $270 to $2,600 for six months.They always have something going on there for the whole family..