Federal motor carrier laws were written to exempt farmers and rv's. If a person is hauling something that he just purchased or is transporting something to where it will be sold, he is classified as a private carrier, but is still regulated by Federal motor carrier safety regulations. If you stay close to home and know the local troopers, you will probably never be bothered. However, if you are involved in an accident, it becomes a serious. I have operated trucks for over 45 years both as a private carrier and as a motor carrier. I have seen people unknowingly get into some pretty ugly situations. "Commerce" is interpreted pretty broadly, and it is difficult to convince a court that you were transporting something merely to take it for a joy ride.