If you make it to rope drop each morning, you can squeeze in all 4 parks in 3.5 days. Did you get the planning DVD from Disney? If so, watch it with your girls to see what cranks their tractors and plan accordingly. My guess is that MK will be highest on their lists. If they are daredevils, Studios has 2 thrill rides that they'll want to hit. Try subscribing to the Unofficial Guide and/or Tour Guide Mike websites for the best days charts they publish. These really help make the most of your time by spending each day in the least crowded park. The touring itineraries really do help you do more stuff without feeling exhausted or rushed. It's impossible to do everything in a week, let alone in 4 days. It is, however, possible to do the best of the best and have a great time while you do it. Remember to take time to enjoy the little things that make Disney so special. You're much more likely to remember the time one of your kids played hide and seek with Peter Pan and Wendy than time you ran off to squeeze in one more ride.
Even though your time is limited, I still think mid-day breaks are worth it. Gives everyone a chance to relax and take a break for the over-stimulation of the parks. Amazing how much difference even an hour or 2 in the pool or inside out of the sun can make in the rest of your day.
What time of year are you going? During summer the parks are open much later, so you can take longer mid-day breaks without really sacrificing touring time.
but maybe your 5 year old can do it. We never return to the hotel during the day, so the stroller is a needed break for my little one.
