Somehow I managed to lose weight on my last trip, despite a Thanksgiving dinner and many a snack in the parks. Once the weather gets nice, I do practically every single money-raising walk that I can. I do the 10 mile MS walk, the 3 mile NCCJ walk, the Corporate Challenge (I even run a little of this). I would say that someone has to walk before they go on vacation, at least to form some callouses and know exactly what shoes do not cause blisters. That little bit of training can save a lot of hassle in the parks. Plus, it will help with that nightly sprint that you will want to take if you really want to get out the parks quickly!