The military campground on Juniper Point at Canyon Lake is two sections. Both cost $25 per day. We spent five days at the Fort Sam side in Jan. 50/W/S site. Plenty of space for your rig. Call early for reservations. They get full in spring and fall, sometimes in summer.
As weather gets better, the campground location gets busy with a lot of folks up from the bases on weekends staying in the rental trailers and small cabins.
The lake is quite low. Not really good for swimming, and you have to be careful about swimming.
We stayed st Lackland AFB FamCamp for a night before going up to Canyon Lake. Nice, but nothing special. We drove through the Fort Sam campground, didn't notice any construction.
Canyon Lake is about an hour and 15 minutes drive from any of the San Antonio attractions. Both the Fort Sam and the Lackland campgrounds have a lot of folks staying there due to medical treatment at Brooks and Wilford Hall.
There are two nice COE campgrounds on Canyon Lake. We prefer Potter Creek, but there are no FHU sites