I would definitely bring your own stroller for the baby, preferably one that reclines and has a sunshade. The big Gracos are hard on the bus, but not impossible, I used to do the bus with a Graco double, but that would probably be the most comfortable for your little one and you wouldn't have to buy anything else. Maclaren makes some great lightweight strollers that are still full- featured, but they are expensive. If you will have dh or someone else with you, you could bring the Graco for the baby and the umbrella for the 5yr old, that way she has somewhere to sit when she gets tired, because she probably will get tired. I am bringing a light weight umbrella style stroller for my dd when we go at the end of this month and she will just be turning 6. You could rent a single for your 5yr old for when she needs it, but I wouldn't use a park stroller for the baby, they aren't that comfortable for infants, really more made for bigger kids. If you are going to be by yourself with the two kids, then I would strongly suggest buying or borrowing a double or a sit n stand type stroller so both kids have a place to sit. Even if you're not by yourself, that type of stroller would be helpful, but if by yourself, I'd consider it essential! Hope you have a great trip!