I came across this note in Fear's Day By Day:
Note: Arthur L. Scott’s article, “The Innocents Adrift Edited by Mark
Twain’s Official Biographer,” PMLA, Vol. 78, No.3, (June, 1963), p.230-7
covers in depth how Paine butchered this piece, which was initially to
be a full-length book. Paine changed the title to “Down the Rhone” and
the castrated version was published in Europe and Elsewhere, 1923.
and read through the article. Now I'm wondering if transcripts of
Twain's original manuscripts are available.