I have nothing in this discussion - being from Canada - but used to travel to Dallas and San Antonio. SAT is about 1.5 hrs from Austin, Dallas is 3.5 hrs? from Austin
I mention this as I think there is a couple from San Antonio who go in Feb to SXM - they wrote a trip report this winter [stayed at a Laure unit?]

Maybe their travel route might help as SAT is closer to Auston than Dallas

J&B