Well, obviously stay out of direct sunlight and wear very very high level sunblock and wide rimmed hat.
Pace yourself, Disney will still be here when you come back, you don’t need to do it all.
Consider renting a ECV or maybe if someone is willing to give you a wheelchair push?
Watch your food, you don’t need anything new and foreign messing with your stomach any more than chemo does. Stick to tried and true and -no matter how tempting- don’t go for extra spicy.
You know when and how your body reacts to your treatment, maybe make that day a resort/pool day?