If you were Miriam and had just delivered a baby, how would you feel about being asked to go wash curtains? Do you think this scene could have any other significance?

I would probably feel the same way Miriam does--not really wanting to do something that arduous after just having a baby. However, this scene is part of the genre of the entire book in that this book parodies the agriculture/naturalism movement in literature. Thus, this scene is an individual parody of the stereotype of the strong farm girl who births her new baby and keeps on plowing.