I had to giggle when I read this. It kinda depends on what you call not far. To hike in Texas, I drive 5 1/2 hours to Lost Maples or 6 1/2 hours to Palo Duro....if I want to hike close then I drive to Arkansas which is only 4 hours away :)
Reliable tubing is probably around Austin/New Braunfels area. You can sometimes tube up here in North Texas but it helps to do so right after a flash flood. Luckily, New Braunfels is only 4 hours away...which is really only just a hop skip and a jump for Texas driving.