I am frequently asked about our route from Iowa to South Texas or South Texas to Iowa. We mix it up usually, sometimes a lot and other times a little here and there. But this is the route we would take if we were making a straight run with out any friends or family visits along the way. This is what we have found to be the best for traffic and the most avoidance of major cities, particularly the stint between Dallas and San Antonio. From Waco to Austin on I 35 is particularly challenging in a motorhome and the years do not seem to make it better.
Here is the link: https://goo.gl/maps/zEozBogyL7m