The designated camping areas in the US forest lands that are "primative" and require self-contained RV's are the best bet for the month of October. I always take the excellent USFS maps for the areas where we will be traveling as these locations are clearly marked along with the various dirt roads in the forest.
Private parks may be open but with campers displaced from the public campgrounds these places are likely to have fewer availablel spaces if they are still open.
Guess we now need to worry about the Tea Party Republicans shutting down the campgrounds in our trip planning. Doubt they lose any sleep over the travails of the little people, including all the employees of the park and forestry service and their families - not going to be a happy Christmas for their children.