We haven't had Thhanksgiving at WDW b/c our crowd numbers in the mid 20's each year, and we'd need at least 2 GV's and that's a LOT of points. We have, however, fixed turkey in our villa before. I would suggest that since you are driving, you pick up your groceries in Florida near the park at Publix. There, they sell a frozen turkey breast that run about 5-7 pounds. THe package label tells you that it goes from freezer to oven to table (I can't remember the brand name, but I'll call my mom later and ask her).
We put our turkey (it comes in it's own self contained bag, so clean-up is a breeze if you choose to use the baking pan in the villa, and not a disposable pan from the store) in the oven and set the "time bake" so that it is ready within an hour or so of when we get back to our room, and then we fix corn, mashed potaoes (I use the fake flake kind, they're so easy), gravy, and etc... maybe some pumpkin pies that you baked and froze at home before leaving. Not everything has to be homemade, I'd suggest that you find the easiest way for side dishes that your family finds acceptable, and go ahead and do the homemade ones for the dishes that your family really has to have. You have a year or so to experiment with canned corn, and powdered gravies to see which are best for your family. I find the kitchens at Disney to be as well stocked as my own (except for a food processor, a George Foreman and a breadmaker!)
Happy Planning!
I agree that taking younger kids out to eat can be a huge waste of $, esp. around a holiday and vacation! I find it easier to eat meals in sometimes...
Laura