We put my DD6 in a stroller at Epcot and Animal Kingdom. It sure helped us get around the WS a lot faster! At AK, we ended up leaving around noon, so it wasn't quite as beneficial. However, we had ADRs at Marrakesh that night and we were running late. Once I remembered that we had a voucher for a stroller, we loaded DD up and made it to our ADRs without a problem. Normally I would say 6 is too old for a stroller. However, after days at WDW, you've got to give the kiddos' feet some rest!