To start answering your question, it would help to know a bit more. From place to place and time to time, farms can be quite different. Are you trying to replicate an 18th or 19th century American farm or a traditional central European farm? Or a farm in traditional British Isles ans Irish style? Or do you want to replicate an early 20th century farm? Or perhaps a modern industrialized farm from somewhere? There are substantial differences among all of these models.