(This picture was taken last winter, no actual snow around here yet. The apparent tilt is the result of the camera-operator - likely me.)
When the clubhouse was new, it was a place for reading, a lookout, an advantage spot in a water gun fight, and a place to keep the toy kitchen and all the bazillions of dishes and plastic food. In the last year, it's become an ignored and empty waste of space. The kids still climb up in there, but now it's just to sit and chat for a few minutes, or stop off on the way further up the tree.
So really the only thing making the difference between a clubhouse and a chicken coop are a door and some insulating. I'll post more pictures of those, the fence, etc. as we go.