Texarkana to San Antonio

Look into I-30 Texarkana to Mt. Pleasant, 271 to Tyler, 155 to Palestine, 79 to Rockdale, 77 to Schulenburg, I-10 to San Antonio. Use the Loops/Bypass in Mt. Pleasant, Tyler and Palestine. You will be on mostly US numbered Highways with 4-lanes, less congestion, fewest red lights and the most constant average speed on this route. It keeps you out of the Austin/I-35 mess and the entire I-35 construction disaster. It might not be the shortest route, but it will be the less frustrating and safest. I've been these routes for 40 years and have watched the progress for the better.
If you draw a straight line Texarkana to SA, you'll see this route is driving towards SA until the US77, Rockdale to Schulenburg jog...475mi and 10hrs at a leisure pace. Wave when you go thru Gilmer!!