Romance at Rainbow's End — Colleen L. Reece

Seven years after Ellianna and Timmy Stoddard are sent to frontier California by their contemptible father, eighteen-year-old Ellie still carries the weight of his sins. Surely a scoundrel's daughter cannot be the answer to the new minister's prayers for a wife!
Joshua Stanhope is also plagued by doubt. Can a small-town preacher compete with his influential twin brother? Edward can make Ellie the toast of San Francisco by helping her soar to fame and fortune like the meadowlark whose song is no sweeter than hers.
Will Ellie find treasure at the end of the rainbow -- or only fool's gold?