I don't own a timeshare, but have always stayed in them when in Orlando. The ones I would recommend would be Orange Lake (OrangeLake.com), any of the Marriott resorts like Grande Vista, Cypress Harbor or Horizons or the Sheraton (Starwood) Vistana Villages. We have stayed at all of these and they are all lovely resorts with a very easy commute to Disney.
The largest is Orange Lake...which is so big that you may actually need to drive to get to a pool. (There are several.)
Hope this helps you out.
Happy Planning!
HeatherC