Hey Victoria!
Having a stroller for your older kids really won't seem odd once you are in the Parks & walking for hours on end. I bet you'll even have other parents remark how smart you are to have had the forethought to bring a stroller from home & not end up spending money on a rental! You will see other kids your daughter's ages in strollers, so they won't be the only older kids in one.
We usually end up renting a stroller for our 6 year old daughter after we've been walking a lot & she's starting to drag. One time my daughter balked at the idea of being in a stroller, but I let her pick some special ribbons & a scarf to tie on the handle (so we could find it in the stroller crowd easily) & once she gussied it up, the stroller was suddenly cool enough for her!
My son just turned 10 last week, but even he looks at the strollers with an envious eye after half a day in the Parks...& I'll be honest; I have totally wished I could curl up in a stroller, too!
Seriously though, if it isn't too much trouble to bring it, then I would go for it. Your kids will be more comfortable which means a smoother trip with more Happy memories for all!
I hope you & your Princesses have a Magical time with pain free tootsies for all!