In the North Texas area, we enjoyed visiting Possum Kingdom State Park. Don't know what it's like after that fire a few years back.
Now if you want to go out west to the Panhandle (which some folks call West Texas), I'd recommend Palo Duro Canyon SP and Caprock Canyon SP, in that order.
I'd stay away from both in the summertime unless you're taking an overnighter on the way to someplace cooler.
2017 Thor Compass 23TR last RV
MV-1 Mobility ventures wheelchair van
DH+DW 36+ years
Millie the fawn brindle greyhound