Dallas National is a broad-shouldered, difficult course. Matt, I've heard a few folks say that DN is built on a great site, but it seemed like a very hilly site cut by deep valleys, and the lowest part of the course is swampy. Not really sure about the soils there, but it would surprise me, I guess, if it was sandy. Regardless, Michael, I think you'd find yourself a good test there, and a good club atmosphere with excellent practice facilities.
And remember, Austin's only a few hours away.