Thanks for the very thoughtful and interesting
responses to my question regarding the route Jim takes
to try for freedom.  There's one other possibility
that strikes me that hasn't been mentioned.  Is it
possible that Jim simply doesn't know that Illinois is
a free State?  I don't imagine slave owners would
advertise how close a chance at getting away really
was, and Huck probably wouldn't tell him because of
his guilt at helping the runaway.  Jim is very
intelligent in many ways, but maybe it's a question of
the availability of the information, not intelligence.
 What do you think?