BITTER MILK (Picador) doesn’t lack for offbeat and entertaining citizens to populate Chilhowee Mountain, the backwoods East Tennessee setting of Austinite JOHN MCMANUS’s first novel. There’s Avery Garland, who suffers from gender dysphoria. And her overweight nine-year-old son, Loren, and his prattling alter ego, Luther. And patriarch Papaw, who’s given to crooning off-color ditties at inappropriate moments. But having birthed his characters, McManus seems unsure what to do with them. Avery disappears to a clinic, leaving Loren to wander from relative to relative. He fishes a little and climbs a roof with Papaw, but there’s not much else going on other than the Garland clan talk, talk, talking in their hillbilly patois. Ultimately, Bitter Milk seems less a novel than a short story in search of an ending.