Walnut Creek Metropolitan Park (East Austin)

The Rundown
Address:  5100 E 51st St, Austin, TX 78723 (Now known as Little Walnut Creek Greenbelt)
Difficulty: Beginner/Intermediate with some super steep short hills
Distance: 4-5 mi combining all the trails
Terrain: Single track dirt with steep short hills. This is sticky clay dirt and slippery rock when wet. 
Ammenities: None
Parking: Street Parking 4899 Tannehill Ln Austin, TX 78723

I stumbled onto this trail a few years ago on a long run with some friends. It is great for those that live on the Eastside! The one way I have found to access it is along the gas pipeline on Tannehill Dr just North of 969/East MLK. 

The trail follows the pipeline for just under 1 mile and then you have the option to move onto single track or stay on the pipeline trail. If you look at the map and see the straight line, that is the pipeline. There is a flat jeep road that parallels the pipeline that is where you run.