DW and I have been using these sites for several years. All campgrounds are in a secure location - on a military base - and have armed guards at the gate. Here's the website for military bases all over the US.
http://www.militarycampgrounds.us/ Click on Recreation Facilities, then USA Map and state listing, then click on the state listing - below the map . go directly to the right page with this:
http://www.militarycampgrounds.us/lo...nas-campground. They allow Active, National Guard, Reservists, Retired, 100% DAV, DoD civilians.
Enjoy!!