I have just booked our 11th trip to WDW and the excitement never wears off!
Even with having been 10 times I keep picking up tips from this forum, but generally dont push your self by trying to stay at a park from morning to night every day .It has always been best for us to either go in morning when the parks open and stay until late afternoon or go to a water park in the morning and then arrive late afternoon and stay until closing
Due to excitement and the time difference you will be up early for at least the first few days, so you will have plenty of time to have breakfast and be at a chosen park when it opens with ease.
We always stay in the WDW area, so we tend to use the first few days to go to Universal area as its a 30 min drive and we are up so early anyway. After that just take it easy, and use the fast passes at the parks.
When we do have a long day in the parks, we go to Epcot in the morning and park there, have fun then some lunch and leave about 2pm, but go by monorail to the Magic Kingdom leaving your car there at Epcot. The monorail ride is great between the 2 parks. Try to hang around where the front of the train is as if your lucky you can ride up front with the driver for an even better view! We stay at Magic kingdom until about 7pm and then get the monorail back to Epcot for the fire works,
There is the new Aquatica water park in the Universal/Sea world area, sounds fantastic, we may well go there our first day.
Enjoy and be prepared to start planning your next trip as soon as you get back
