Half sisters Carin and Hope predictably become friends on their road trip across the western US. Carin always flies from Iowa to Nevada for her summer visit with her father. But because crabby older sister Hope has to drive from Chicago for a job interview, this year Carin will join her on the road. Despite her irritation, map-loving Carin enjoys noting the miles covered, and she builds a map of their route out of used chewing gum in an old Whitman’s Sampler box. Several small adventures later—after swiping food from a class reunion, having a car breakdown, surviving an encounter with a scary old lady, and running out of both money and time—the girls have progressed from sniping to hugging. Some nice details in this otherwise lightweight, oddly paced tale. (Fiction. 10-12)