OH I have another tip that I SWEAR by on vacation...
Eat like you do at home at the restaurants.
I am a VERY healthy eater at home- aka the whole organic, mostly vegetarian, etc. thing. So does my husband because I'm the one that cooks in the family

When we're on vacation, my DH likes to eat things he doesn't normally get at home- burgers, fries, pizza, etc... JUST BECAUSE HE'S ON VACATION.
Ok, the whole 'just because you're on vacation' thing doesn't sit well, and for me, it LITERALLY doesn't sit well. If I eat crap while I'm on vacation, JUST BECAUSE I'M ON VACATION, I'm not going to have a very good vacation because I'm not going to FEEL GOOD.
If I'm on vacation, I don't know about you, but I want to FEEL GOOD!!! Therefore, I look at wdwinfo.com at the restaurant menus, and pick and choose what I'm going to eat and find the healthiest options possible, that fit in to my normal eating pattern.
I bring snacks from home like organic granola bars, smooshed fruit leathers, fresh fruit, etc. and keep them with me in the parks and in the room.
So, don't eat crap when you're on vacation, just because you're on vacation.
Soapbox sermon over.