Creator Breakdown: Twain ran into writer's block at several points during the writing process; the way the story goes off the rails at the end was one result.
Write What You Know: Twain incorporated many events from his own life and adventures on the Mississippi into the fictional narrative. Two of the best examples are Colonel Sherburn's killing of Boggs and Huck finding the runaway Jim on the island, both of which were based on things that Twain actually witnessed firsthand. Both of these incidents were worse in Real Life, however. The original of Colonel Sherburn was acquitted on self-defense charges, and the slave Twain found on the island had been tortured to death by slavehunters and left to rot. In case any of you are interested in traveling, St. Petersburg is Hannibal, MO, where you can camp outside of the cave and buy passage on a boat that will take you right past 'Jackson's Island' (making it easier to find later). 'Cardiff Hill' has a lighthouse on it. Be warned, however: the town knows that Mark Twain is its selling point, and they are capitalizing on it.
Write Who You Know: Most of the townsfolk in St. Petersburg are based on members of Twain's family and his childhood friends from Hannibal, Missouri. Huck and Jim themselves are based on the son of the town drunk and a slave Twain's uncle owned.