take Congress Ave. south of Slaughter lane. Cut through the parking lot of Akins High School, to Old San Antonio Rd. You can take that to Cabela's in Buda or take a left on Puryear Rd. and take that to Creedmoor. However, I haven't been on the Creedmoor leg for awhile since they recently finished construction on a tollway over there. I don't know what it is like now that construction is finished.
To the west on Slaughter, you can connect with Loop 1 South to Camp Ben McCullough Rd. This is a high speed 4 lane road, but has a wide shoulder that is heavily used by cyclists. It will also take you to the veloway, which is a 2 lane blacktop 5km closed loop, exclusively for bikes and rollerblades.
You can actually take Old San Antonio all the way to San Marcos, but the traffic getting through Buda has gotten to be a real pain.
There used to be some good maps on the Hill Country AIDS Ride page, but I can't find them now.