It depends on time of year, dining plans and EMH. For example, on my trip in Feb during President's week, our flight landed at 5pm, so MK was really the only option for a 7pm arrival at a park (that night the MK closed at midnight). Also, if crowds are light, AK and DHS can be completely taken care of in less than a day. For the last trip, over 6 days/5 nights, we were at the MK 3x, and Epcot, DHS and AK once.