What's the meaning of "roaming" and "unlikely" in this context?

Hi Guys. I have been reading the biography of Sherwood Anderson. I come across with a few words that I couldn't understand their meaning in the context. I highlight those words and I will appreciate if someone can help me. Thank You! Sherwood Anderson born in Camden, Ohio, is often called "the mid-American Chekhov." He inherited his gift of narrative fiction from his father, a roaming, improvident storyteller of unlikely tales.