I have attended either 2 or 3 games in DKR in the past 10 years and here's my takeaways (two of the games were vs. ranked Okie State teams, so big, important games against a ranked conference opponent):
1. Stadium is big but, at least when I attended, not especially loud and raucous
2. UT fans treated us very nicely but we weren't wearing opp team's colors, either
3. Co-eds in sun dresses, cowboy hats and boots - in abundance and they're spectacular
4. The games I attended were late Sept/early Oct games and it's still plenty hot; drink plenty of water, lather up sunscreen
5. Austin is difficult to navigate in the best of times, home football games only make a bad traffic situation worse
6. Parking is problematic but we managed to find a garage for a reasonable price; patience pays off
7. Somewhat similar to A&M, UT has several 'traditional' cheers, fight songs, etc. that, when they're winning, you'll hear a LOT
8. Cheer team in chaps? Yes, please.
9. Good atmosphere, just not rabid like many SEC venues. With basically no history of UT and UK playing, I wouldn't expect any animosity (until after we've kicked their ass, of course)
10. Austin can be a lot fun to stick around, grab some grub, take in some live music; unfortunately, friends of mine who live in the area have told me that their status as sanctuary city has led to a ton of immigrants, much higher crime, etc. Be careful.