Texas has built or rebuilt some REALLY nice rest areas in many locations on major highways around the state. They do have very nice air conditioned/heated restrooms, very nice playgrounds, snacks/drinks, and even free wifi. They often have interpretive displays, typically about the local area to that rest area.
But they do not have RV hookups of any kind. And they no longer have dump stations, probably due to abuse of the privilege. They have big rig parking slots, but that is typically just for stopping long enough to use the facilities. Although I think they do allow overnight parking also.
There are still many of the older rest areas yet to be renovated, so check their map if you intend to try to schedule travel around them.
We passed by the one just south of Hillsboro last month and it did appear near completion but did not appear to be open yet. The one south of Temple/Salado has been open several years and is very nice. Same for the two different ones on US 287 between Wichita Falls and Amarillo.