Texas has the "Castle Doctrine", i.e. a man's house is his castle. We aren't "required" to retreat against a threat in our house like a lot of other states. The law changed on 9/1/07. You can also carry a firearm in your car when "travelling" which was redefined as any time you are in your car. You don't need a CHL for that. As far as shooting someone on your land tresspassing, I'm not sure of that, but I would suggest that you not test it in Texas.....we take our hunting land very seriously, and don't like people wandering on to it.
As far as public land hunting, it is rather limited, usually to permit draw hunts put on by the Texas Parks and Wildlife Dept. or on some federal lands like the Hagerman area just north of where I live.
As far as guns, we have a ten gun minimum down here.....any less than that, you will have to buy some more before coming.
JK