DH and I took our 4 DDs in January of 2011 for 6 days. Their ages were 3, 5, 7, and 9. We had adjoining rooms at POP which was nice for the evenings and the extra bathroom!
We had a double stroller, water, snacks and autograph books! We didn't do naps either and they were all fine. If the two younger ones were tired, they would fall asleep in the stroller. That didn't happen too often though! We had a plan for each day and our ADRs were chosen with input from the girls. We spent two days each at MK and Epcot, and one day each at AK and DHS. Believe it or not the girls chose to spend a second day at Epcot!
We had an amazing week just the six of us! Enjoy the memories you will make!