E.B.
In my opinion, many families plan a pretty rigid schedule. "First we'll go to this ride, then that one, then we have to go to this exhibit", etc, leaving no room for freedom and spontaneity. It applies to tourism spots as well as theme parks and fairs.
We've lived in many countries and I have observed the occasional family that has a schedule on their phones or in a guide book. They're so intent on reaching Stop#4 that they have completely missed a wonderful opportunity that was right next to them, had they been just relaxed and enjoying the moment. But they were too intent on staying on the plan.
One time when we were at Disney, we planned on going to a particular ride, but the kids had so much fun on the ride that we just had been on that they wanted to go again. We never did get to the next ride, but the kids had a wonderful time, and my husband and I realized that spontaneity was more important than the anticipated schedule.
It's pretty impossible to see everything and do everything at these large parks, so let that just go. Enjoy what's right in front of you. Stop and listen and watch and if your kids want to look at something and stop and enjoy something, just let them.
Prepare your kids by telling them that you'll do what is possible, that there will be some things you just won't have time for, but that the fun they'll have will be something they'll enjoy for a long time.
Also, don't spend every second taking photos. Take just a few. Instead, look at your kids' faces with your own eyes, listen to their laughter.
Another possibly helpful tip is to plan the souvenirs ahead of time. When kids walk into that gift shop, they just want everything they see. It's mesmerizing! Plan on one t shirt, or one hat, or whatever their interest is and according to your budget. And save the purchase for the very last day, before exiting. Use the gift shops along the way to help narrow down their choices. Then on the last day, they'll be able to say "Yes, I've decided, and I really want that magic wand" or they'll have completely forgotten about the thing they just couldn't live without on the first day. Get the souvenir when departing on the last day (plus that saves lugging around bags and reduces the possibility of misplacing a hat or toy during the previous days). Make sure your kids understand that and stick to it.
Have fun!!!