I have the Sit and Stand stroller by Baby Trend and used it on our last trip to Disney in November. I had a 13 month old, my DD turned 4 while she was there my DS was 6. Most of the time the baby rode in the front while DD4 sat in the back. We hung the diaper bad over the handles and she used that to rest her head on. My DD is very tall and weighs 48 lbs. She would occaisionally climb in the front while the baby wanted to be held and DS sat in the back. She didn't complain of being uncomfortably but did need help getting out. When she and DS were both in it , it was very difficult to push but not impossible. It was nice to have somewhere for them both to sit. It is not at all hard to fold up. Just a little big but no big deal. No one complained on the busses. I figured for what it would cost to rent a double stroller for over a week, I could do something nicer with the money. If I were only going for one day, I would consider renting. We have a single stroller but when we go back in May, we're definitely taking the double. It's a little more difficult to push but that's because it's bigger. It's really not that big of a deal to be. If it helps you decide, my son weighs about 50 lbs. so I was pushing almost 100 when they were both riding but I think you'll find your son won't want to ride that much. Mine just wanted to occaisionally ride for a break. (You might do ok with a single stroller and swap off for a while.) Good luck and have fun!