About halfway between the two is the Gruene historic district which is a great way to spend an afternoon. It's a charming old town with a lot of shopping, antiques, etc and sit's on a beautiful stretch of river. This area is known for tubing in the rivers too, fun place to explore and a great stop imho.
Best wishes -Jim
Wimberley is another little town outside of Austin. Lots of little shops to browse. For Austin, depends on what you like to do, but it's mostly an eating and drinking town. Tons of breweries around. For outdoor things: Hamilton Pool, Riemers Ranch, Mckinney Falls park, Zilker park and Mt Bonnel. South Congress is popular for tourism with lots of shopping and the Continental Club. The Domain is a popular shopping district. You could always visit the Capital or see if there are any bands in town that interest you.