Last year we spent 2 full park days-park hoppers, in a 10 -day stay. It was great. We did MK 1 1/2 days and Epcot 1/2 day.
What did we do: Pool hopped, resort hopped, wilderness campground camfire w/movie, GF-watched MK fireworks, rode the monorail btwn locations and just soaked in all the magic that was there. There is plenty of it.
We were w/ my in-laws and they di not have park-hoppers and only bought 2 single day passes.
The kids did not miss it-they loved going to the pools!