About a month ago, I had to be in Austin for business the weekend I'd planned a 15-mile run. Needless to say, I wasn't looking forward to hitting the hotel treadmill, so I was excited to try out the Town Lake Trail a friend had recommended. It's a very picturesque 10-mile or so trail on both sides of the river (connected by bridges at several points) that is quite close to the downtown hotels and popular with locals. Perfect. Or so I thought, until it started raining. The rain washed away the soil, at which point I realized the trail was constructed out of concrete (on top of which they'd placed about a millimeter of soil). It probably doesn't make much of a difference for the dog walkers and casual joggers, but 13 miles on concrete left me with a raging case of plantar fasciitis in both feet. A month later, I can barely walk. (I'm pretty careful about my running -- form, shoes, varying workouts, etc. -- so even though I typically run 20-25 miles / week when not training, the last time I had to take off more than a couple days because of an injury was more than two years ago.)
Long story short, stay away from the Town Lake Trail for serious runs!
Somewhere in the world someone is training when you are not. When you race him, he will win.
As an Austinite, I am quite familiar with the Town Lake Trail. While there are portions of the Trail that are concrete, where washout is a problem, the concrete sections are few and far between. The majority of the trail is crushed granite. Many Austin runners, including distance runners, run the Trail not just the casual walkers and dog walkers. Marathon training courses take place on the Trail. No better place to enjoy the beautiful Texas sunshine.