We went on a Saturday so it was PAA-cked! Took us 3 whole hours to driving the whole thing. At one point, we thought we were going to run out of gas. We were sitting in line on a decline and I guess our gas tank couldn't detect the gas in the tank so it told us we had zero miles left of driving. Freaked us out until we started driving again and the gas gauge went back up. We totally started thinking of how we were going to get gas in our cars. My first thought was to call my dad to bring some to us since they live only 30 minutes away. Thankfully we didn't have to play out that thought.
Near the middle point of the park, there's a store and a petting zoo that you can get out of your car to go potty, eat, shop and pet the animals. It's a nice "stretch your legs" break, too.
If you live near the DFW area, we highly recommend you visiting this park. Although, the next time we go we'll be sure to go on a week day!