When it comes to selling produce, farmers have a few options. There are grocery stores, then there are farmers markets. In Kansas City, mobile markets are even cropping up. Check out that story,here. Now, we bring you barebones farmers on wheels. Road bikes are the preferred form of travel and mode of commerce for the operators of Quail Bone Farm in Columbia, Mo. Listen to this week's Field Notes to go inside their world: a night peddling freshly picked vegetables on the streets.