Ed. note -- bumped from FanPosts
It is that time of year that Austinites both love and, with each passing year, increasingly dread: SXSW. If you are one of the few looking to get a good run between 20-min live sets, free beer, and pretending that you knew twitter was going to be huge in 2006, know that Austin is brilliant place to get some miles in. Below I've highlighted 3 areas that connect through the downtown area. There are many more in and around the city but if you are visiting for SXSW, it is likely you'll be in the downtown core.
1. Town Lake hike & bike trail.
This is the crown jewel of trails for the road runner set. The full loop is 10 miles but there are points to create 3, 5, 7 mile loop variations. Water is stocked in several spots on the trail by local running stores and there are water faucets throughout. Similar to the path around the Charles River in Boston but nicer path surfaces, more isolated from cars / roads, and with better people watching. There is only a few short sections along a road or concrete and only 1 section where you have to cross an intersection with a light. The path averages 15,000 people per day and twice that on the weekends, so it can be crowded, especially the sections located right downtown. It thins out quite a bit once you get east of Congress Bridge. If it has been dry, some sections gets dusty from all the people running.
The trail has many access points which is handy because driving anywhere downtown during SXSW is pretty much a non-starter.
2. Barton Creek Greenbelt.
Linked with the Town lake trail via Zilker Park is the Barton Creen Greenbelt with over 40 miles of trails. It is an fantastic park that starts in the heart of the city and works it way south. The main 'super highway' trail follows the creek and is 7.5 miles end-to-end. It is well marked, includes mileage markers, and not super technical (it can't be if mountain bikers ride it).
There are 3 main sections to the park. Lower, Wilderness, and Travis Country. Lower starts at Zilker Park downtown and covers about about the first 4 miles of the trail along the creek. In this section there are limited opportunities to find trails off the main trail, it is hard to get that lost. There are likely to be more people and you'll find rock climbers sprinkled throughout. Pop off the trail at the Spyglass access point and grab some running fuel at Tacodeli.
Upper starts at the Gaines / 360 entrances and follows the trails up to the end. The volume of people thin out a bit on the trails here though if it is warm out you'll find packs of people at the swimming holes located by any of the falls. It is straight up 1979 action at the swimming holes during the summer: little clothing, cheap beer, guitar, and ill-conceived facial hair. Trail is nice and easy along the creek. If there is water in the creek (and there is currently), you'll have to ford the creek to get all the way up to the end. There are few spurs and sections off the main trail that offer more a more rugged experience.
Travis Country isn't on the map linked above and the parks department doesn't maintain an official map. It is also where all the really fun trails are located. On the map linked above those blue lines snaking to the south up by the Spring and Sculpture Falls lead up in to Travis Country. The trails vary from well worn and in moderate use to a trickle along the rocks that get only a few uses per week depending the weather. I do not recommend this section unless you are with a guide or you are used to exploring new trails. The trails twist around a lot and double back so it is easy to get turned around. There are times when I've run out there for 4+ hours and not seen a single person. It is wonderful how remote feeling it is even though it is still in the heart of Austin.
3. Shoal Creek. Hike / bike path going from Town Lake north up to central Austin. Nice enough but no reason to go run this by itself. It is handy to know that you can park a bit north of downtown and then run down to Town Lake. Saves the hassle of traffic and parking down near the lake. Map here. Can be popular with college kids as it runs along the west campus housing of UT. Sections used to be a frisbee golf course but they closed it for causing too much damage to the park.