Mapping tools are fantastic for setting up rides, figuring out mileage, planning multi-day trips, etc.

But for finding good, ridable roads there is *no* substitute for getting advice and stealing ideas from others. *Especially* since you are from Austin, you should check around for the "favorite" routes of local clubs and groups. Most times they post their routes online for you to look at. Look up every shop ride, randonneur route, touring club ride, and organized charity ride, century, etc. that you can find in the area. If you dive into the routes that these rides take, you'll quickly figure out that there are "favorite" routes that get used over and over. Also, check sites like www.bikely.com or www.mapmyride.com to see the rides that other local riders have already mapped out.

You still have to use some caution and skepticism -- but stealing ideas from clubs and organized routes will show you lots of good places to ride.

(BTW, there is a club called "Hill Country Bicycle Touring Club," based in San Antonio, I think, that has posted lots of Hill Country routes on their website....)