Are you planning to go back to the room for naps? If not, do the umbrellas recline? There wasn't a single trip when my kids were that little that they didn't fall asleep in the strollers at least once.

We've used all kinds of strollers on our trips, but the best by far was a Graco side-by-side that was sort of a cross between an umbrella and larger stroller. My big kids were 4 and 2 at the time. It was lightweight and easy to fold but allowed for individually reclining seats and had an awning on top.

If you decide on the umbrellas, you can find rigid attachments that connect the two together that essentially make them a side-by-side, so you don't need two people to push.