One of the first camping trips I had with my son was Guadalupe River State Park.  We tent camped and had one of the primitive sites.  We had so much fun swimming in the river and hiking.  We worked with the park Ranger program and my son was awarded a Ranger Badge.  The bluffs above the river are gorgeous.  Mid November and swimming was still fun.  The next morning was 10 degrees so a whole different experience.  One of my favorite places to visit.