Go stop by a small town nearby! Sisterdale, Blanco, Johnson City, Luckenbach, Gruene
Hop over to New Braunfels and enjoy the sun and float the Guadalupe or Comal river! You could rent tubes from Texas Tubes in NB or any of the HEBs have some tubes for $20. The tube chute is a great starting point!
Guadalupe River State Park Enchanted Rock State Park
Visit the missions in San Antonio, stop over by the Pearl for lunch/drink as well