How are part 3 and 4 of the novel different than the parts 1 and 2, in terms of the focus of the story?

How are part 3 and 4 of the novel different than the parts 1 and 2, in terms of the focus of the story? What new themes, motifs or narrative techniques do we discover here? In what sense is the novel engaging with ideas of gender roles women are expected to play then and now? Most of the historical sources of the novel come from men. Is this in any way important or meaningful?https://www.gutenberg.org/files/467/467-h/467-h.htm