Go to state parks website and you can look up all these...
http://www.tpwd.state.tx.us/spdest/
http://www.tpwd.state.tx.us/spdest/findadest/parks/ray_ro...
That Isle du Bois area of Lake Ray Roberts is great! There's a lake with a beach area -- the kids love it! But we've done tent camping and pop-up camper camping there.... the tent area that we were at ... you have to park in a parking lot and walk a little ways to get to the tent site. (when you're carrying tents, sleeping bags, cooking pans, etc ... that's a hike!) ... so if you go there (it's probably closest to you).... call to see if there's a tent area that allows you to park next to the site. Our pop-up camper site ... that allowed us to park next to the site, but you pay more for those sites and those may be just reserved for camper vehicles.
http://www.tpwd.state.tx.us/spdest/findadest/parks/cedar_...
There's Cedar Hill State Park - gorgeous area! wooded. There's a lake there w/a beach area, but that beach area can get crowded on the weekends (in the summer they are).
http://www.tpwd.state.tx.us/spdest/findadest/parks/tyler/
Tyler SP - the most gorgeous -- in East Texas ... heavily wooded. You can park next to your tent site. The thing I've noticed here... it tends to rain almost every time we go! But that's how they have those gorgeous TALL trees!!
http://www.tpwd.state.tx.us/spdest/findadest/parks/eisenh...
Eisenhower SP in North TX on the state border. There's a lake here, but the swimming area does not have a beach. You can park next to your tent sites here.
http://www.tpwd.state.tx.us/spdest/findadest/parks/dinosa...
Dinosaur Valley in Glen Rose is really cute for the kids!! Kinda a long drive, but worth it! Not more than 2 hrs though. There's a creek area, where the river runs through it ... and it's by the picnic park area.... the kids love to get wet there, splash in the water! I have some great pictures of my son playing there. good memories!