High of 91 today here in Laredo (86 right now), though here at the campground in my fav spot (nope, won't divulge which particular site, I want it available as possible when I show up; I even call ahead sometimes
) there is *such* a sweet breeze, I can't understand why anyone would sit in their van all day on a hot blacktop parking lot up at the truck stops. That just increases your chance of feeling discouraged.
$18/night gets you your own site with water and electric, your own good shelter and picnic table, and access to either of two shower houses. One is much newer and nicer than the other. Locked entrance gate at night and each camper gets the combo to the gate lock if you come in late from dinner, etc.
You can also just pay the day use fee of $4 and can picnic and use the showers.
If you get an annual Texas State Park Pass from Texas Parks & Wildlife (
http://www.tpwd.state.tx.us/spdest/parkinfo/passes/ ) you don't have to pay the day use fee at any Texas state park, and get a discount on a set amount of overnights. I got $9 off one night with this stay. You can reserve a spot online, too, if you think it will be a busy night or weekend at whichever Texas state park you choose to use.
There's another good one north of Dallas on Joe Pool Lake called Cedar Hill SP.