>>24611374 (OP)
Josiah Flynt was this weird guy who hung around with hobos & criminals. He was sort of one of them but not entirely.
He wrote some good stuff about them. He was one of the first people to study underworld slang seriously (he introduced a lot of words into general use: "speakeasy", "pinch", "squeal", etc.)
He died aged about 25 or something from a drug overdose, IIRC.
Might be a bit too lowlife (not exactly Victorian Gentleman Adventuring) but interesting. Similar:
— “The Road" (Jack London)
— "Autobiography of a Super-Tramp" (W. H. Davies)