In all honesty, the gun stores I've seen in TX are hardly any different than those in SoCal. Don't come here expecting vast showrooms and endless selection...at least around Dallas.
I've wanted to go to Collectors Firearms but haven't made it down there yet. Sounds interesting.
If you like used/collector guns and are in Dallas, Jackson Armory is amusing. I've taken a few people there and most have enjoyed it. It isn't a huge shop but they have some interesting stock.
There is a Beretta Gallery in Dallas. Not sure if that's your thing.
If you are looking for stuff you may not see every day in SoCal, Military Gun Supply in Ft Worth is hit or miss but might be OK.
From a SoCalers perspective Cabela's, Gander Mountain, and so on can be a bit of a trip. It's corporate retail, sure, but still not what you normally see in Clipper Town. If you go to Cabela's, try to go to the Ft Worth store.