My recollection was Doc Gibbs was a dentist, but whatever, Grand Prix Raceway was a nice venue in the middle of that great expanse of West Texas. I've been to Fort Hood a few times for my former employer, too. In times past, I've lived in Bristol, TN, and Saginaw, TX, with a family living in Mesa, AZ, so I've made a few road trips back and forth and look for raceways along the way. My wife's family is in Virginia, so we're still taking road trips back and forth.
I read somewhere, probably one of the blogs/forums, that Doc Gibbs died some time ago, and when he did, he left the slot car stuff to a group of Odessa/Midland slot racers. They had to move a few times chasing affordable space, and selling the Sovereign enabled them to keep going for a while longer. However, my understanding is there's no active raceway or club in this area now.