Disnee Dad Says...................................If it's only one park or the other, then it's EPCOT hands down. Three times as much things to see, and open 33% longer than AK. DD loved EPCOT at ages 7,9,11. Wanted to learn and study and find museums! All of a sudden at age 12 on our last trip none of that mattered! It was shopping!!! So she still loved EPCOT.
If hopping is possible, I'd pop AK early and hit Safaris first, then Kali River Rapids, ITTBAB, Primeval Whirl,TriceraTop Spin, Dinosaur, and a little play time at The Boneyard. Maybe try to catch Lion King and or Pocahontas, and your out by lunch time.
Out by lunch time as in the food at AK is really lacking. WE eat at Tusker house, nice chicken, but at EPCOT you have 10 times the choices! Go to World Showcase and try something new. Last trip we ate at Teppanyaki, and one couple at our grill had never tried Japanese food before. They got a fantastic show, wonderful food, and great conversation, as did we! Did Norway for lunch, a buffet. It's not all fish, it was great, any place that has smoked salmon and pork roast on the menu gets my vote!
Then there is Illuminations (I start to choke up, grab my Millennium Celebration CD and I'm ok,lol ). Not to be missed!!!!!