My thoughts- The special room with the tree was the deepest part of yourself. It is warm and open once you get there, but to get there it takes a lot of work and effort climbing so many stairs. The many rooms are the various aspects of yourself, you want to capture all of them with the camera, but because it is lost, the parts of yourself are illusive, and you cannot see them all or preserve them all as a whole. I think your dream demonstrates a respect for your inner self, and a desire for wholeness.

-Ariel

Whatever you can do,
Or dream you can, begin it.
Boldness has genius, power, and magic, in it.
-Goethe