Austin's Half Ironman is the longest triathlon in the Austin area. The swim is held in Decker Lake, the site of many of the triathlons in the Austin area. The lake is not clear, but it is not too muddy. Expect some weeds near the shoreline.
The bike is a single 56-mile loop around Decker Lake on some roads that don't have a lot of traffic but can be chip-sealed and in poor condition. The course is east of Austin, so it is not very hilly.
The run is three loops on a pavement - it looks like the run course got rid of the grassy jeep trails and the Quadzilla Hill!
T3 is one of the top triathlon training programs in Austin - they offer core workouts, spin workouts, stroke clinics, long bike rides, and Ironman Training Programs. They come highly recommended for athletes who are willing to put in the training work to do their first Ironman or to improve their times.