The need for a stroller is a personal decision. Our youngest is now 8, but we didn't need a stroller when we went for his 4th birthday. We usually spend 12-14 hours per day at the parks, but we do not have any complaining about being tired even with the walk back to HoJo at the end of the day. Every child is different, some have no problems with long days of walking, with others it can turn the trip into a nightmare if the walking expectations are too high. My advice see how it goes, if your kids are no longer having fun because they are exhausted then get a stroller.