Why not get into something that won't interfere with your farming. See a lot of this double dipping. You can't serve two masters. Nevermind in the same field. Your dad is right. You want to sell something make it snowplows. night vision googles. Anything that won't get in the way. Other poster is right why would someone buy something and not expect service when called.
  Don't get me wrong,I am all for doing something.Just pick something away from your day job.