Old Hwy 90 out of San Antonio then on to Beaumont...
https://maps.google.com/maps?oe=utf-...ed=0CC4Q8gEwAA
But it would be much more scenic going through Bastrop, Brenham, Conroe, Beaumont, Lake Charles...
Sorry this auto link not working - The route I first described is a common old route used for bicycles and smaller motorcycles - In 1970 my buddy and I once rode our Honda 125s to Lake Charles and back over a long weekend - We were only 15 and 16 so we stayed off the mains...