Up and Down the Scratchy Mountains — Laurel Snyder

THIS IS THE tale of Lucy and her best friend, Wynston. Until recently, they spent their days paddling in the river, picking blackberries, and teasing each other mercilessly. But now, King Desmond has insisted that Wynston devote every spare second to ruby-shining and princess-finding. Lucy feels left out. So she sets off for the Scratchy Mountains to solve the mystery of her missing mother. When Wynston discovers that Lucy is gone, he tears after her, and together they embark on a series of strange and wonderful adventures.