What I'm pretty sure of is that Carl Cornelius was a friend of Willie Nelson, and Willie had a couple of his 4th of July picnics there. Cornelius incorporated the town because Hill County was dry and he wanted to be able to sell alcohol.
When I drove by there a few years ago, there was a "trucker's chapel" set up in the parking lot. I heard that Carl's son had been killed in a drunk driving accident (don't know whether the son or the other driver was drunk or anything else) and that the incident had broken Carl, and he decided to quit selling alcohol and let the place fall apart. Now, the son getting killed and everything is rumor; I have no idea whether it's true or not. I do know that Carl's Corner went from this outlaw advertising on the highway to having a Christian chapel in the parking lot, and that I never see it open anymore.
I know Willie started the Bio Willie thing, it eventually was sold at around twenty stations, but that most of them have quit selling it, and the billboard advertising it on I35 is gone. I have no idea if it's even in business anymore.