If you get into the Texas Hill Country (Between Austin & San Antonio), you might want to check out Pedernales Falls State Park. I stayed there for a week over Thanksgiving on my way from Dallas to my Kerrville-area winter home. They have huge
campsites with electric & water, nice concrete picnic table with grill & fire pit; all for around $20/night. Also, plenty of deer & turkeys, hiking trails, the "falls", several wineries in the area, and grocery, convenience stores, and gas stations within 10 miles. All made for a very enjoyable stay!