disney ready,
You're in for a great vacation! If you guys get up early, then early entry is the way to go, since you can experience a number of attractions before the park gets crowded. The summer crowds will be building in mid June. What I like to do is go to the early entry park, use FASTPASS when it gets crowded, then leave after lunch to rest or swim at the hotel, and return to another park for late afternoon and evening. If you don't get up early, go to a non early entry park and use FASTPASS for the popular attractions. Try to fit in one or more character meals; it's a great way to get character autographs. You can easily walk several miles or more per day in each park. When someone gets tired or hungry or too hot, it's time to take a break! Finally, it's good to have a plan while in the parks, so everyone doesn't argue about what to do next. So I recommend one of the touring plan guidebooks (like the one I wrote! see below).
Steven Barrett, author of the "Hassle-Free Walt Disney World Vacation" and the new "Hidden Mickeys of Walt Disney World" book