I've been in a similiar situation as yours and here's what I've done. I agree about the HUGE double strollers, they aren't ery comfortable to bring and for a 4 almost 5 year old, the child probably will e too big to get comfortable. There are two side by sides which aren't very big and actually aren't very heavy. The Maclaren double and the Combi Twin Savvy. The problem with almost any double is that they aren't made for a larger child. The Combi is the only double that is certified for children up to 45 lbs per side, but it's rather low to the ground and larger children have a hard time keeping their feet up. The Maclaren is probably the best double for a larger child in my opinion, but their seats are narrower than most, and if your child is very slim you'll be o.k. but if not another uncomfortable situation. Any of the tandem strolelrs will be a disaster in my opinion. the front seats are WAY too small for any child over 3, and the child in the back won't be able to see anything anyway. Even with the stadium style seating, the larger child will block the little one, and make for a bad situation, also they are just so darn big and heavy!!! I personally don't like the Sit and Stand stroller, I think it's too bulky and heavy to lug around WDW. I've found what I think is the perfect stroller for a little kid and a larger toddler. I use the Peg Perego Pliko. It is a VERY lightweight stroller, as well as easy to fold and carry. There also is a small place on the back for the older child to stand. It works out great, since my almost 5 year old watned to walk most of the time in WDW, and only started riding when she got tired. I also thought of lugging two strollers, but dismissed it, with the thought of trying to get on/off the busses. You'll have to carry the baby, and keep track of the 5 year old, who usually still need assistance off the bus. Just too much lugging in my opinion.