I think a certain location is mentioned, perhaps in the letter that the Fist sitting by Art will give you? If you find and explore that location, that might help. Also, if you inspect Art and consider what you know of him, then it might help you get an idea of what you're looking for.

It does involve venturing a way away from the Inn.

"You may call it 'nonsense' if you like, but I've heard nonsense, compared with which that would be as sensible as a dictionary!"