We can't get across the state in 8 hours so not much. Maybe Austin, south Arkansas for hiking/outdoor activities, south Oklahoma for Broken Bow, or Shreveport, LA for gambling/river. There are a few small TX towns a little over 3 hours like Fredricksburg where you can B&B and do wineries/breweries and hiking. Five hours would get us further like touching the beach in Galveston but probably need at least an 8 hour drive to get to another state and do something fun like Hot Springs, skiing, New Mexico, you could get close to New Orleans, etc.