One wouldn't instinctively think of "easy clinches" and Texas in the same thought, but US 96 can be clinched in less than a day. Same with US 57, of course -- but the problem with that one is the distance involved getting TO the route, not over it! Oh -- US 181 -- at least you stand a good chance of finding some above-average food at either end, the termini being in decent-sized cities!