I am a regular player of FarmVillae @ Facebook. Every time when i log in to FarmVillae to harvest my farm or to grow crops, it takes much time as i have a large farm. The farm vehicles can help you for some time till you have a good amount of Fuel. But what happens when you fuel is empty.
I found a way to reduce the time in harvesting by applying this technique. The main delay is that the farm walk from one plot to another to harvest it. If the farmer takes 1 second to walk from one plot to another and if you have 600 plots, the time consumed by the farmer to walk is 10 minutes.
Now you can save this 10 minutes by locking the farmer in one place. I have locked my farmer in one place by moving him from the plot to any place in the farm where all the four sides are closed. I achieved this by using Hay Bale or you can also use fence or crate.
This should be done for one time, each time you log into the game. Then the farmer will remain in this place without moving from one plot to other. This save much time if you have your sub farm at a distance and even to harvest Trees or animals.
I have demonstrated the locking in this image. Hope this may have helped you, if so let me know in the comment section.