In rough order of my preference...
Marriott Cypress Harbour
Marriott Grande Vista
The new Marriott Lakeshore Reserve
Sheraton's Vistana Villages
Marriott Sabal Palms
Marriott Imperial Palm Villas
Marriott Royal Palms
Cypress Pointe Resort
Marriott Harbour Lake
Sheraton's Vistana Resort
Cypress Pointe Grand Villas
All of these resorts are between 7 and 14 miles of the Magic Kingdom parking lot, so pretty close to Disney. These resorts are of relatively high quality and provide a nice resort experience. It's worth looking at the resort descriptions at both the Interval site and at the individual resort's sites to determine which one makes the most sense for you and your family.
Dick Taylor