We've always had conversations, read trivia about the rides (printed and in my park bag), gone through pictures on the camera/phone, went over and over and over park maps (that day's park and the ones we were going to in the days ahead as well), talked about our trip, what we've experienced that we liked, wanted to do again, etc.
I've also read that pipe cleaners can keep a kid occupied. Small, easy to bring along, won't annoy other guests. We bring Wiki-Sticks (like pipe cleaners, kinda). They've been an easy, convenient, sure occupier at restaurants, planes, waiting rooms, etc since DD was 2. She's now 11!