I also read I Been There Before, and recommend it.  In
addition, this discussion brought to mind Philip Jose Farmer's
Riverworld series, in particular the Fabulous Riverboat.  Farmer
obviously did a lot of homework on Twain, although he misses the
boat somewhat on the man's personality.  Farmer's Twain did not
have that recognizeable sense of humor.

Terry Ballard
Adelphi University