Make sure you take advantage of fastpass. If you are at MK when the gates open, go directly to fantasyland, get a fastpass for Mickey's philharmagic--even if there is no line. It will tell you to come back at 10:05-11:05, and you can get another fastpass at 10:10 ( I might be off by 5 min. or so.). Most people will go to philharmagic and if there is no line, see it then. Philharmagic is fairly long compared to other attractions, so while you are inside, lines are forming at other attractions. After getting your fastpass, you can ride anything in fantasyland or go to the haunted mansion, thunder mtn, splash mtn before any lines form. Then, before using your fastpass, take the train to the other side of the park, ride space mtn or buzz lightyear, get a fastpass for the one you don't ride,and go back to philharmagic. While you are there the time will be ticking on your second fastpass. I do the same thing at AK getting a FP for the safari first thing.
I went to MK before work one day just to see how many things I could do in the couple hours I had before heading for the boats (this was during March--spring break). In 2 hours and 10 min, I was able to do 8 rides and had 2 fastpasses just by being there when the park opened. If you slow down a little and can still do half that--you'll have a blast!
My "don't miss list"
MK--Philharmagic, haunted mansion, and the "Mountains"
AK--Festival of the Lion King (my favorite of any WDW attraction bar none), Kilimanjaro safari
MGM--Rock 'n' Roller Coaster, Fantasmic
EPCOT--I like the entire park. Too much to see, too little time in a day. IllumiNations is great.
Food--
Ohana at the Poly is my favorite, followed by Boma at AKL. Trails End restaurant at FW is the best value in WDW--good food, reasonable prices,and the best breakfast on property.
Have fun,
Bill