We don't usually nap, that's a rarity. If we go to the park first thing in the a.m. we take an afternoon break sometime between 12 and 2. We usually have a nice quiet lunch some place, perhaps take a swim, or go shopping, minature golf...something like that. Something non-park. Naps just don't happen for us, but we don't have kids. I think kids would wear us out, plus they need naps themselves. We like to take a break during the hottest part of the day and then return later that night for fireworks or parades and EMH if it's happening.
Sometimes we'll opt to not start our day in a park. We'll swim, shop, go to Fort Wilderness, resort hop...something non-park in the a.m. Then we'll go to the parks in the afternoon or after a late lunch/early dinner. We can't handle a whole day in a park at once. I'd say the longest we'll stay at one time is 5-6 hours.
PamNC