First up, I have a different edition of the text than everyone else, so apologies that I don't have page numbers that are helpful. Moving on, I took particular interest in Huck's deliberation in chapter XXXI.
Here, Huck resolves to go to hell for helping Jim rather than do the "right" thing and allow him to be sold back into slavery.
This whole issue and Huck's treatment of the moral standing of his actions - believing himself to be in the wrong for helping Jim, yet resolving to do it anyway - makes for an interesting close reading of Huck's (and indirectly, the novel's) relationship to race.
While one might suggest that Huck is "doing the right thing" or even challenging racism or slavery by deciding to assist Jim, Huck's own interpretation of his actions clearly stand against this view. He clearly articulates that he "would take up wickedness again, which was in my line, being brung up to it, and the other warn't."
While we might see this merely as an internalization of social standards about ethical conduct involving blacks/escaped slaves at the time, that Huck has merely been exposed to, we also must note that he does not make a point to reject this interpretation of his actions as wrong.
In fact, rather than seize the opportunity to grow morally and condemn society's treatment of blacks, slaves, escaped slaves, or anything along those lines, Huck goes a ways to enforce his actions as morally wrong, by saying that "if I could think up anything worse, I would do that, too; because as long as I was in, and in for good, I might as well go the whole hog."
While I originally read this deliberation as progressive on Huck's part, I can't help but think it's morally ambiguous at best.
Huck seems to fundamentally lack the ability to see past moral judgement's he's absorbed from his surroundings, despite actively working against them in some capacity. And by absorbing them and articulating them by judging his own actions as immoral, Huck enforces those views almost more so than he fights them.
I don't think the temptation to read this section under the light of "actions speak louder than words" is sufficient justification. I don't think we can read Huck's choice as socially progressive, and am inclined to say that we ought to read it as harmful.
To illustrate this, I think it's fair to transpose Huck's deliberation to another social issue. Imagine a comparable case:
Workplace Gender Discrimination: X, a woman in a corporate job, is paid significantly less than her male peers, gets fewer benefits, and receives less leniency from her superiors than her male peers, for no other reason than her gender. X's boss is eventually replaced by a new boss, call him Y, who notices X's predicament. Y belongs to an unusual religious group that has taught him to believe that women are fundamentally inferior to men, and should not be treated as equals. In fact, Y believes it is immoral, damning even, to treat women on the same plane as men. Despite this, Y likes X, and decides to treat her the same as her male peers. Y openly bemoans this in his private writings, admitting that he thinks it's likely he'll go to hell for doing something so immoral.
In a case like this, can we really be convinced that Y, because of his actions, is a social progressive, or an aid to feminism? Do his actions in any way outweigh his intentions? I think not. In fact, I think in both cases we ought to be convinced that the intentions even outweigh the actions of both parties, and that on the whole, both are more oppressive than they are liberating.