Consider two places that I know of.
1) Rayford Crossing in The Woodlands just north of Houston. AWESOME resort!
2) San Gabriel RV Park in Georgetown Texas.. just north side of Austin. Gorgeous! On a river, and easy access to Austin, Frederickburg, Chappel Hill, Houston, Dallas, San Antonio. No great place is more than 3 hours from here.
Actually, I'm sitting there right now
Very nice park in a beautiful area of texas.