Mike, take a look at the chapter on the ending in James Cox's -_Mark Twain: The Fate of Humor_. Also, I have to agree with the other Mike's assessment of your reaction to the verb "deconstruct." Deconstruction is not something new, but a new description of a rhetorical activity that is very old. I think the idea that Twain "decenters" his novel in the ending, thus robbing the reader of any sense of self-righteousness that may have accumulated alnong the river, is consistent with Twain's methods in several other instances.