Commoner by Choice by Judith B. Glad
The heyday of gold discoveries is over in Idaho Territory, but there are still fortunes to be found. Eliza Jane Dollarhide believes that one is buried somewhere near a tiny mining camp deep in the wilderness. Her guide is Micah King, young, widowed, highly recommended--and Black. Never having known a person of color, Eliza is at first apprehensive, but soon learns that Micah is both a gentleman and a superbly competent guide. A good thing, too, for soon after they reach the isolated gold mining town of Yellowjacket, they realize they face deadly danger. Someone is after the papers Eliza came to retrieve, and will stop at nothing, not even wanton murder, to get them. Only one road leads out of Yellowjacket, so Micah guides Eliza along a dangerous trail through the wilderness, depending on dim memories of a long-ago journey through almost impenetrable mountains. As they travel, each learns to know the other, and soon love blooms between them. Impossible love, for Eliza is white. So even if they survive their ordeal--and escape whoever is trying to kill them--sooner or later they will have to part. Or will they? Surely there must be a way they can be together, be happy.