I suggest parking further and taking shuttle easy in and easy out. Also the small events like the petting zoo and reptile house closes at 8. Rodeo starts at 7:30 and concerts usually start at 10:00.
The Fajita & Rib Corral has the best BBQ and 100% of the proceeds go to scholarships, unlike the rest of the vendors which operate at 45%... I was volunteering there today and man that food was delish
Most places (food, drink, and marketplace shops) on the fairgrounds are cash only. Don't forget to grab some from the atm before you come to avoid atm fees!