Sorry for the long delay in response.
Well if you after pigs you can pretty much go anywhere in the state... we are absolutely overrun with them. one of the guys who supports my forum runs an outfit called DoubleDrop Hunts and they pretty much have their hands in everything your looking for. They are located in Central Texas and run a year around operation. The guy you will be contacting there is named Ryan, hes a pretty good guy.
You could also look into the King Ranch, they run alot of pig/javelina hunts outside of deer season at reasonable prices. They are located in South Texas along the coast about 5 hours south of Houston.
As far as snakes go... well, some times are better than others but we dont ever fully get rid of them. Texas temps are so mild and unpredicatable that they could be 6 feet deep one day and sunning the next. The winter months your chance of an encounter goes way down... Hogs and predators are plentiful statewide, but the two areas i just described you would be very likely to atleast see some Rattlesnakes.