A Good Man Is Hard to Find by Flannery O'Connor (1955). O'Connor grew up in Milledgeville, Georgia, and her short fiction is as close to essential reading as south Georgia has. The title story — a family road trip through the Georgia countryside that ends in violence — is unsettling in the way that good Southern Gothic should be. Her characters are all flawed and recognizable, her humor is pitch-black, and her landscape is unmistakably this part of the world. Read her before or after driving through it.
Midnight in the Garden of Good and Evil by John Berendt (1994). Set in Savannah, a few hours northeast, but it illuminates the deep-South world that Valdosta exists within: old money, racial tension, eccentricity, and a justice system that operates according to its own logic. The book reads like a novel but it's journalism. If you're driving the I-75 corridor, Savannah is worth a detour, and this book is the reason to care about it.
Walking with the Wind: A Memoir of the Movement by John Lewis (1998). Lewis was from Pike County, Georgia, and his memoir traces the Civil Rights Movement from its Alabama roots through the legislative battles in Washington. South Georgia was shaped profoundly by the civil rights era — Valdosta included — and Lewis's account gives that history a personal, specific weight. It's one of the clearest accounts of what the movement actually looked and felt like from the inside.