Hike out a quick (but steep) few miles and have giant campsites all to yourself! Sweet silence besides a few cows. Classic Texas Camping.
Starting at the Cedar Brake Outer Loop trailhead, leave your car and toss your pack on your back. You'll walk along some pretty single track-style paths and depending on what season you've chosen, you might be treated to some lovely Texas wildflowers. You'll come to a river crossing and get to cool off (possibly holding your bag above your head). The trail continues on the other side of the river.
There are several routes you can take to get to your campsite. Campsite 4 is the one you're aiming for, and the park trail map is detailed and can show you some options. Cedar Ridge is more of a gradual slope, but if you're up for a challenge, go by way of the Buckeye Trail. Camp 4 is large enough for several tents, so be sure to bring your buddies! And after you've had your fill of camping, stop by the Blue Hole Trail to see some dinosaur tracks and to wash off the "camp smell." And if you're planning on doing a lot of hiking in Texas, pick up a Texas State Park Pass. For $75 you and a car full of friends have access to all Texas State Parks for a full year!