Chapter 27: Jo begins to make money at her writing, and publishes several small "sensational" stories, as well as her first novel.
Chapter 28: Meg and John begin their life together. We read of some of her mishaps. She tries currant jelly, which won't jell, and then gets upset because John forgot and chose that day to bring home an unexpected guest. Meg also gives into temptation to live beyond her means, and they quarrel over money. However, mostly, it's a very happy marriage. The chapter ends with the introduction of their new twins, Daisy and Demi.
Chapter 29: I think this must be a set-up for something still to come, as it doesn't seem like much happened in this chapter. Amy and Jo went visiting, and they don't suit each other very well in this task: Amy likes to do it decorously, socially correctly, and Jo doesn't like to do it at all, and isn't very accommodating. Aunt March decides something during their visit, but we are not yet told what.
It seems to me that most of the "scrapes" mentioned in these chapters could have been avoided by making small adjustments in manners. Meg & John were not really communicating very well (which is pretty normal in a new marriage: communication is difficult!) but had Meg not been so terribly determined to not take family problems to her parents' house the whole thing could have been improved, at least. Plus, given that dinner was her responsibility (they both expected she would be the one that did the cooking), it really was rude to leave John and his guest hungry. She could have made up a little something that would have been better than exposing the disagreement to someone who truly WAS an outsider! That's a bit ironic, in my opinion, given the exaggerated "don't run home to Mama" posture they're taking. Jo, once she agreed to go with Amy, should have done a good job. Even the folks they visited hadn't been aware of her strange behavior, it wasn't a kind thing to do to Amy. Apparently, it's going to have repercussions...