I love this part as well, especially the bit about the journal! I think it further reinforces Austen's emphasis in this novel on the ordinary, as opposed to the drama of the Gothic novels she mentions. I've read a bit of Udolpho but not much besides, so I don't know if I'm correct in imagining there to be scores of tall dark strangers. Henry seems rather the opposite, though - not quite handsome, straightforward, a bit quirky, and they talk about writing styles and muslins!