You have quite a bit of good advice on here, but I'll throw my two cents (maybe three with inflation) in as well. NORMALLY, I never use the first day as a park day. For once, I feel like if I'm not there for most of the day, I'm not getting value out of the tickets I paid for. For two, I like having the ability to sort of take an "appetizer" before getting the full meal so to speak. What I mean, is basically, do like some others have said and sort of "wet their appetites" before going to the parks. My old tradition was to spend the first day in Downtown Disney, usually checking out the new merch and going to DisneyQuest. DisneyQuest has made me very sad last time I saw it (it really is a shell of its former self), so I doubt I'll go back there, but for grandkids, it might be perfect (it's basically an arcade, but has lots of cool stuff there like the Buzz Lightyear bumper cars). It is a little pricey, though, so I'm not sure what your budget is. You can always play in the arcade, walk around the resort, go to the pool, etc. There are some really good places to eat in DTD as well. If you want some theming, there's always T-Rex or Rainforest Cafe. Me personally, I always loved the anticipation that built up the night before going into the park. I used to work there and I STILL get that same giddy feeling the night before going into the park when I come back. We are going on a Disney Cruise which stops by the park in May and I'm already counting down the days. It really comes down to how many days you'll be there, what they like, etc. My routine is - arrival day - Downtown Disney, first day - Magic Kingdom and maybe Epcot, then from there I just play it by ear. I prefer Magic Kingdom first just because it will always be what I think of when I think of WDW (My first visit there as a kid was pre-Epcot, so MK was all there was).