George, we stayed at the RV park below in Arlington which is between FT. Worth and Dallas when we visited some friends from the forum. It kind of put us in the middle of everything and was a nice place to stay.
http://www.treetopsrvvillage.com/
I am sure some of the other folks on the forum can help you some of the other cities and the site below is one I use a lot to find different parks in Texas. You can also register with them for free and they will send you a card to get 10% off at any of the parks listed on their site.
http://www.texascampgrounds.com/find_a_park.php
Odessa and Midland are pretty close to each other so you might seach on either for a park. RV Park Reviews is another good place to look. I hope some of this helps. When are you headed to Texas?