If this is your first time Magic Kingdom it will be the most special place of all! It's really important to plan so that you leave happy and not stressed that you didn't do XYZ. Having said that, you still won't see and do it all so don't worry if you can't.
In planning your vacation, first decide if you want to MK on the first day or wether you might like to save the "best" for last! I would do the later!! Next, AK is really a half day park as it closes early (usually 5:00pm) so I would sandwich that in between going to Epcot and MK.
If I were you, this is what I would do...
First Day: MGM. Must do's in my book: everything - lol. Unless you have really little kids I would try and hit it all and it's totally doable. If you don't have little kids, skip Playhouse Disney and Honey I Shrunk the Kid's playground but don't miss the afternoon parade - it's pretty good! Lastly, don't miss Fantasmic!!!!!!!!!!!
Second Day: Epcot. Spend some time in Innoventions East or West but don't let time get away from you. Go to Coke and do the taste test! Don't miss: Turtle Talk with Crush, The Living Seas (again don't let time get away!), MS, TT, and Maelstrom. You can't possibly see and do everything in Epcot in one day but those are the biggies in my book. Explore as many countries as you can and hit the kidcot stations but quickly (if they still have them). We love Epcot! Lastly stay for Illuminations at night!
Third Day: AK. Grab a fast pass for EE and then run to do the Safari first thing. After that, it's all up to you. We just like to wander when here and whatever we do, we do. Really look closely at the Tree of Life. Bug's Life is neat but not if you have little ones. Look at the animals and soak in the side shows here and there. Jammin' Jungle parade is neat - you won't see it anywhere else so try not to miss! Take lots of pics (if that's your thing) there is much to photograph. Not a great plan, I'm afraid! Go back to hotel and swim if it's nice and then hit the hay for your last, most fun-filled day!!!!!
Last and 4th Day: MK!!!!!! You've waited for this day and now it's here! Get there early and don't miss Mickey's Philharmagic, Buzz Lightyear, Splash Mountain, Space Mountain, Winnie the Pooh (if you have little ones), all of Fantasyland, Haunted Mansion, and mostly don't miss the parade and WISHES!!!!! Things to skip IMHO if pressed for time: Tiki Room, Riverboat, Stitch, Astro Orbiter, and Train ride. All else is gravy!! End the night with Wishes fireworks (awesome!) and you will have had a wonderful vacation!!!!!!!!!
HTH and have fun! Good luck with your planning!
