Agricultural Rates

I would like to know the best way to haul Potatoes, when there’s large weight times in between loading and unloading. Second is how can I calculate my freight rate if I cold call to potato plants or dry bed hauls. I want to stick locally not more than 3-4 hours away. Thank you in advance, I am trying to gather the numbers I need to be able to start up my trucking business and make profit eventually after having everything paid off.