Eighteenth century politics, rhetorical styles, lost-in (space or time)
literature, revolution, musical comedy (Bing Crosby, William Bendix, I
think)
...there are lots of ways to discuss this little novel.

Yet another would be from the perspective of original sin, or if that is
too strong, man as a flawed creature.  There are some parallels, for
example, with another 19th century novel that wasn't a big hit at the time
but is now recognized as one of the monuments of American literature--Moby
Dick.  In both cases you see central characters who are doomed by their
imperfection.  You could also argue that for both authors this is pretty
consistent with what we know of their views on humanity.  There are other
parallels--both novels involve travel, and considerable action and adventure
provide a palatable and entertaining setting for the underlying messages.

Mike Dooris--Penn State