Showing Death Train to Boston by Dianne Day

Death Train to Boston Caroline Fremont Jones and her partner, Michael Kossoff, are traveling incognito on a train to Boston to investigate a series of accidents when the train blows up, separating the couple. While Michael searches for her, Fremont is "saved" by the leader of a Mormon sect and held captive in a remote cabin. Unless she can escape, she'll become his sixth wife. Full description