Definitely follow the kids' lead and don't be afraid to change your strategy day-to-day. My girl is not a stroller napper, so we did the AC lunch, leave at 2pm plan;but we never made it back out to the parks (unless it was a walk into Epcot from the Boardwalk hotels). On our last trip, we spent the mornings swimming, had an early lunch and nap, then hit the parks during the afternoons/evenings. If the kids can sleep in the car, maybe you could squeeze a nap in between a park hop? Or a few rounds on the monorail?