Southern Tradition. Traditionally speaking, a picnic roast is defined as a pork shoulder roast, which is considered the fattest and toughest part of a pig. Southern cooks typically smoke or barbecue the roast for long periods of time and refer to it as pulled pork or a picnic roast.hatever the cut of pork roast, the meat can be seasoned by using a needle to inject flavoring solution into the meat. A blend of apple juice, cider vinegar and Worcestershire sauce makes a tasty solution. Then use a seasoning rub, and slow-cook the roast in the oven or smoker. Serve with barbecue sauce on the side.