Holidaying in Texas in December
I will be visiting the U.S. from Australia in December/January with my wife to visit our son in Louisiana for Christmas, and then we'll all take a road-trip to see some Texas. We've been to Austin before on another trip and loved it so would love to get out and see more this trip. We have 3 weeks and a car. Driving big distances to see things is no problem. I'm already thinking the hill country and Fredricksburg area and would be keen to see a good national or state park, e.g. Big Bend). Your tips for any Texas "must dos", "must-sees" and "best avoideds" will be gratefully received, thanks.
UPDATE: Wow! That's gold. A huge thank you to everyone for taking the time to share your local knowledge... there are so many great suggestions here, it's really helping us plan a great itinerary. I really appreciate you all.