I don't think you are nuts, but you will have to be realistic as others have mentioned above.
We have been over Thanksgiving and the beginning of December, and the Christmas decorations and events are spectacular. Well worth putting up with higher crowds, if Christmas is your time frame to go.
But, be prepared for extremely long lines for rides, massive crowds maneuvering through the parks, and encounters with some tourist Grinches, lol.
Also, on these high attendance days, there is always the chance that a park may close due to reaching its capacity. The MK is the most likely to do this, as well as Hollywood Studios and Animal Kingdom. As you will be staying on property, you will at least be directed to another park where you will be guaranteed admission (a perk for staying on site). It will not matter if you have dining "reservations" so be prepared to get to the park early the day you are dining there, especially the MK.