I found a lengthy but fun route last weekend that started at Volente, continued up to Lago Vista, then back roads over to 183, and back to Austin.
I will post details this evening when I get back to my GPS mapping software at home.
I also found a *superior* quality drive from S. Austin to Fredericksburg. I'll post those details, too. And I would *really* like to do the Willow City Loop.