You already have some good information, but nobody answered you about Harvest Hosts. They, like some others, promise only a flat place. It may be a vineyard, a farm, a museum (and now golf courses not with my membership). I still think it is worth the price. You may feel like you need to buy something from the host (at a vineyard?) but that is not in the contract.
Are you sure you want to go real boondocking? That means that the only thing available is a sort of flat place and fresh air.
There are lots of resources, take your time to find them and talk to others.
Matt