There are many, many choices for traditional T-giving meals at most of the restaurants at or near Disney World...at the resorts, in the parks, at Downtown Disney...
We go every T-giving and have had some terrific traditional meals, some "w/a twist"...probably one of the best, believe it or not, is the counter service turkey (and all the trimmings) meal at Artiste's Palette at SSR! Fancy, no...tasty and very very traditional, yes...it's not fine dining, but it's real turkey w/sweet & mashed potatoes, stuffing, green beans, cranberry sauce, a roll, pumpkin pie--for $10!
We've also had other really good ones, too...more of the "fine dining" type...loved what we got at California Grille (except they didn't have pumpkin pie, a must for me at T-giving), and probably my absolute favorite is the family style meal at Garden Grill at the Land at Epcot...I've heard Liberty Tree Tavern at MK is really good, too, but haven't been to that one...my only T-giving meal disappointment, in the 10 years (or so) that we've been doing T-giving at Disney was an excellent meal at Shula's at the Dolphin...but when I'd made the reservation, I'd asked if they'd serve turkey & trimmings; they said yes...but when we got there they didn't have a turkey meal. The rest of my family was delighted w/the steaks (and they were really good), but I wanted turkey...that was the year I discovered the turkey meal at SSR...(I had one at around 9:30 at night--dinner had been at 5) and it made me feel like I'd actually had T-giving dinner!)...
Best way to check it out is the restaurant menus--they have them here on the DIS (
www.wdwinfo.com/wdwinfo/dining.htm) or at allears.net ...
Don't know how early in the year the holiday menus are posted, but they are definitely posted early enough to snag a good reservation...
Good luck...