Drive to Gonzales, TX. Eat dinner in Gonzales (I recommend Johnny's Cajun Cafe or Baker Boys BBQ), and set up camp at Lake Wood Recreation Area. You could of course choose to stay in a hotel in Gonzales instead. You'll stay here for two nights.
This day is spent driving a triangular route (which could be driven in either direction) connecting four cute small towns, with historic downtowns and boutique shopping in each: Shiner, Hallettsville, Yoakum, and Cuero. Hallettsville and Cuero have beautiful old county courthouses as well. Be sure to tour the Spoetzl Brewery (open only on weekdays) in Shiner; Shiner beer is famous and very popular throughout Texas. I would allow at least a couple of hours in Shiner and an hour-plus in each of the other towns. Eat a late lunch at Mayo's Tacos or BBQ Shack in Yoakum (both closed Sun & Mon).