Find a location near downtown, maybe on the south side of Lady Bird Lake, formerly Town Lake. You want the Sixth St. area (north of the lake) for the live music, & downtown has many great restaurants at all price points. There's a good food truck park on the south side on Barton Springs Rd (try The Mighty Cone). The lake (really the Colorado River, dammed at both ends) has a nice running path on both sides, leading to Zilker Park. You can also rent kayaks, canoes, water bikes, & standing paddle boards along the lakeshore. Austin Duck Adventures is a corny but fun way to get a land & water tour of downtown Austin & Lake Austin (a dam separates it from Lady Bird Lake); the "duck" vehicle is amphibious. At sunset, watch the world's largest urban bat colony fly out from the Congress Ave. bridge -- grab a spot on the lawn near the Austin-American Stateman or a boat trip to see them. While the University of Texas is north of the Capitol & St. Edward's University is south of the lake, college students are not likely to be much of a factor in the summer.