My mom & I were on WW when we went to Disney World. Let me just tell you, it's not easy to stay on the points, while there. Yes, the walking helps, and we'd always get in the pool and move around some more once thre crowds died down a bit (dinner time, after 11). Definately take your snacks with you. When you eat out get grilled items, typically we had grilled chix. sand (no mayo) or some sort of salad while my DH and bro were noshing on burgers/fried chix. & fries. Also, water, water, and more water. I think I actually ate less because I got in so much extra water, of course I often ate more points at dinner because of the large meals. And I agree with sticking to the sample sizes of things.
One thing I didn't try but will the next time I go on vacation is to ask for half portions, they can box the other half for you, and if you choose to keep it, you can put it in the in room fridge if there is one.
Good luck and have a fabulous time!