I used the hole in the wall and walked halfway around the outside of the building and managed to land on top of it. Without dying. (20-30 minute process)
Success! I thought.
"Needs a key"
...
.sad.
So here's why I'm posting about it.
I would love it if someone on PC could navigate to this chest and work some console magic to reveal what's in this darn chest.
EDIT: Pictures, just for fun.
drive.google[dot]com/folder/d/0BzqveGUXr0FuMTVGTkhnMWRYQ1E/edit