i happen to live in Florida..hope you have a great trip! Not sure how long you've been on the meds, but took a long time for the swelling to go down in my feet. I think I live in soft, gushy flip flops. When I go into a flare, that seems to be one of the first places it shows up!
Perhaps if the swelling is too bad, you could call your doc before you go?? Otherwise maybe drink more water, and keep your feet up as much as possible..I know that's easier said than done, but it does help sometimes.
You could always wait and buy your sandals when you get here...there are so many different kinds in the stores, you just might find exactly what you need!