We were there during the Christmas season last year (December 10-18)and it appeared that everyone was decorating everything they could. We decorated our windows but there were some people that decorated doors, windows, the railing outside their doors and anything else they could.
I really wish I would have taken a picture of the first 3 rooms you come to in the Play-Doh building on the 1st floor right across from the Hippy Dippy pool (I think rooms 4110-4112). There were 3 families (probably traveling together) and they looked like they had moved in! They had EVERYTHING decorated, from the windows, doors, they have christmas lights, they even decorated the bushes across the front of their rooms! Each one of them had Christmas tree's and moving annomated figures of Mickey, Minnie, Donald, Daisy and Pluto (throughout the 3 rooms). They had brought Christmas Disney bedspreads and changed them out and had Disney Christmas stuffed animals all over their room decorating it. It was crazy! I can only imagine they must have been staying a while since it had to have taken them a full day just to decorate their rooms!
I think you will be fine decorating the door