His ancestors were prospectors, so it's natural that Peter C. Brown would mine his family history for this gold rush-set story, The Fugitive Wife. The spouse on the run is Essie, a gutsy Minnesota girl fleeing farm life and a drunken husband, who sails to Alaska on a ship full of starry-eyed dreamers. She also finds a kindred spirit and eventual tentmate in the idealistic Nate. Like the characters' voyage, Brown's frosty tale has tumultuous beginnings; talk of sluices and hydraulic dredges test one's patience. And while Brown unearths a few precious nuggets of poetry (''You get within a hundred miles of gold, you can hear it whisper''), this overwrought epic doesn't yield the riches it promises.