How old are the kids? And will you absolutely definitely need two strollers at all your destinations?

I'd do everything within my power to figure how to do this with one stroller only--if you have a baby and a toddler, could you do carrier/stroller or stroller/walker? Could you get a small umbrella stroller to check? Could you rent a stroller at destinations?

These probably only work if you have 2 singletons, though--not sure any of them are good if you have 18 month old twins.