The characters that populate Charles Frazier’s new novel “The Trackers” are all searching for something. The narrator, Val, has journeyed from Virginia to Wyoming in 1937 to paint a mural in a post office as part of the Works Progress Administration, one of FDR’s projects to employ artists in the wake of the Great Depression. The landscape shifts from Wyoming to Florida to Seattle to San Francisco as Val travels the country, searching for Eve and revealing secrets that will change everything bet