If you can make it before the Christmas hols then go for it, the parks are quiet and the decorations are up making it extra magical!
I've been for a week on 4 occassions, 3 times around about 3rd or 4th December and once at the very end of October. It's always just been adults no kids. I have always seen everything I wanted to because of fastpass and travelling at very quiet times of year. I always get to the parks at opening as well and know the attractions that I want to see.
Not sure how we managed it but me and hubby did Seaworld,Universal Studios, Islands of Adventure, Magic Kingdom, MGM, Animal Kingdom, Epcot, Blizzard Beach and still managed to fit a day in at the beach! Granted it was 2002 and we got round Magic Kingdom by 1pm then park hopped to MGM in the one day but we really did see most things we wanted to.
Last year I went on a travel agents visit and a lot of the week we were visiting hotels but again we still managed 2 days at Disney (4 parks), 2 days at Universal and a day at Seaworld.
It's all about planning and making decisions about what attractions, parades etc you want to see but I honestly don't feel that I missed out by only going for a week
