Depends on how you feel, how your kids are doing, how busy the park is, and how many days total you are there.
If you're there for only 2-3 days, your kids are older and don't get wiped out, and the parks aren't, like, slamming, sure, you could hang out all day. I'd just take a bit of a break somewhere quiet in the parks for a half hour or an hour when you get tired midafternoon, like for a snack break on the lower level of Hungry Bear restaurant (with goodies from Pooh's Corner, MMmmmm). Or Pirate's Lair, or Redwood Challenge in CA.
If you're there for 3-5 days, your kids are younger (say 10 and younger); you'll have lots of time to get everything in, and still take midday breaks. Breaks are wonderful (for the parents as well as the kids), because you can just get sensory overload after awhile. If you're staying in walking distance, even 2 hours out of the parks is very refreshing. I would avoid feeling like you must be running full tilt at all times to "get the full worth" out of your stay.
I always remember reading that part in Unofficial Guide from a mom who said, "Take the nap, take the nap, TAKE THE NAP!" Because she would start seeing, around 5 p.m., cranky kids who finally fell asleep in their strollers JUST about the time the parents wanted them to be awake and polite for their Blue Bayou PS's, etc. And the parents would be cranky, too.
When we were there in Oct. and the parks closed at 6 and 8, we still took breaks and enjoyed them very much. We were there for 3 full days and 2 partial days, and had plenty of time to do all we wanted.
