Hogs are considered varmints in Texas, and can be hunted year around. I do believe you need a hunting license though.
Still no way to specifically answer your terrain question. Just come with a rifle that is capable of reaching out there a ways. I live in North Texas, and hunt hogs in a variety of areas, from brush which reduces ranges somewhat to very large, wide open fields.
Since they are varmints, there are no caliber restrictions that I am aware of. As I mentioned before, long shots are possible.
There are various methods for whacking pigs. I like to ambush them as they enter/exit fields. Also, they are definitely corn eaters and will clean up a deer feeder so stand hunting is always good.
Hunt them using the same tactics that you do when deer hunting. Hog hunting is a lot of fun, but its not overly difficult.