Don't attempt this until you can teleport there automatically, because it's a long road from Megaton, and not one that's easy to do. Rivet City is far away, tucked in the southeast corner of the map. We opted to do the historical aspect of the chapter first, which will bring us to Rivet City.
You can do the three things here in any order you so desire (you'll be greeted with three choices representing the three sections of the final chapter). Chapter three will then begin, and this is the final chapter.
