What makes a good Americana song a good Americana song, you ask? Heartache. Longing. Homesickness for a place you can't return to. The road that took the one you love away and won't bring them back. Loss; the person, place and thing. Also, a memorable melody. This week on Double Americana we'll cover the traditional tune, "Red River Valley," a song that even if you don't know it, you know it. It goes by other names including "Cowboy Love Song", "Bright Sherman Valley", "Brigh