To be frank, just throwing everything at the wall will result in victory in very short order, the pre-war US army was just that stupidly powerful by today's standards. Maybe not quite as refined, but that doesn't matter when the everyone is running around with rayguns and gauss rifles. We also never really get to see pre-war armor in FO1-2, although if it's anything in relation to infantry weapons they must've been fierce too.Hmm if you were a Pre-War General launching an invasion into Ukraine what troop/army composition would you use to win?
Try to go for least amount of troops/manpower/resources needed.