I'm giving serious thought myself to doing the same thing. This morning on the radio, a state Representative (Jerry Patterson) was talking about 30-06 signs and such. Jerry is one of the original folks who got us concealed carry and is also in the plaintiffs with S G Hupp filing lawsuits against cities who sue gunmakers.
Mr. Patterson was very informative. Texas has a preemption clause in the Constitution. He was explaining that while PRIVATE property may post 30-06 signs and be legal, no municipality (except courts and a few other federally restricted places) may ban you from wearing your gun. First of all, if it is concealed, no body will know. Second, only the legislature may dictate how guns may be carried or worn (state constitution), and while private property owners such as 7-eleven or circle K might post a sign for which you must obey, the Capitol Metro buses, VIA Buses (San Antonio), and Metro buses in Houston have no legal leg to stand on to refuse you admission due to your gun unless the state legislature allows them that power for which they specifically have not.
Criminal trespass with a firearm is only applicable to private or restricted areas. You cannot trespass on public property during normal business hours. Key word is Public. Those 30-06 signs they post are a bluff.
Anyhow, I suppose as soon as I find a willing and qualified instructor, I'll take the course and pay my fee.