Oh, we also forgot the neutral site against Alabama (also Texas).
I have it on good authority that the Badgers want to have a travel game for every class that's a cool destination, whether that's California, Hawaii, Law Vegas, or some place like it. I suspect playing in an NFL stadium in Texas fits that bill. The economics of it make powderpuff games in Madison a sure thing. So there's one game per season--maybe every two because of the home/away scheduling--that's available for that game.
Before Alvarez was the AD, there were also at Oregon, at Oregon State, at UNLV, at San Diego State, and at San Jose State, though the latter two were probably scheduled before the Badgers were any good (San Diego and the San Francisco Bay Area are nice places to visit, though).
I would bet that Athens, because of its proximity to Atlanta, Baton Rouge, Chapel Hill/Durham, Charlottesville, Miami or Tallahassee, and Austin are all places that would fit the AD's perspective about nice travel games.