We are doing a 3-night AKV Kidani/4-night BLT split-stay in March (just a week total unfortunately), and the plan is:
Arrive Saturday early afternoon, spend the rest of the day lounging around the Kidani pool, dinner at Boma.
Sunday at Animal Kingdom park, Monday at Universal Islands of Adventure (mainly Harry Potter, truth be told), Tuesday at MK (wake up in AKV, go to bed in BLT, have bell services move our stuff), Wednesday at EPCOT, Thursday and Friday are tossups, one day at a waterpark, one at DHS, or if rainy, a day at Disney Quest. Saving money by not buying park hopping or water parks.