Texas has a 51% rule - and there has to be a sign posted, although I've never tempted fate to go find one. And yes, going through the bar to get from restaurant to toilets could be deemed illegal, but unless you have an issue in the bar, cross a TABC agent, or try to open carry, I doubt that transit would be an issue.

But go sit down in the bar area? You should know better. The fanatics will start calling 911 (seen that happen).

And +1 on the RESEARCH! I cross three states every few weeks. All three have different rules.