I actually disagree about only spending a half day at Epcot. That is because I am partial to that park, my DD first went there at 2 1/2 and it's her favorite park, and being at the Swan or Dolphin, it's a very pleasant short walk to the International Gateway.
I find it's nice to start the day in another park, but end in Epcot where you are staying at an Epcot resort. That way, you can just walk back to your room at night (or take the boat if you feel like it).
Really, though, enjoy what you are seeing and doing. In four days, you will absolutely not see everything (I haven't in all my trips). But you should pick the things you really want to see and go from there.
If you are into the Playhouse Disney, there is some show at DHS. My kids are older, so we've never done that.
We do like DAK, but if there is one park you may want to save for another visit, that may be it. It's fun to see the animals and go on the safari, and Dinosaur is cool, but a bit frightening (my son was a bit scared at first). There is a lot there, but it may take a whole day. We enjoy taking it slow there, seeing the animals, riding Expedition Everest, eating at the new Tusker House.
I agree about getting to MK early. It gets quite crowded by lunchtime, so our plan is always to leave there by then. It's just I'm not crazy about the food there compared to Epcot. Also, we've had some really good meals at DHS - both Sci Fi and 50's Prime Time. If you do eat lunch at a counter service at MK, it's good to do it a bit early and know where you are eating. I know Cosmic Ray's can get crowded!
I love the Swan and Dolphin - actually for me, the Swan I prefer as it's a bit quieter and has queen beds. The pool is very nice, the service is good (they have kids menus for room service and movies on demand, for those evenings when you are just too tired to be out). The location is my favorite as well!