I didn't know there was such a fascinating backstory there to be worked with, and give McCrumb much credit for how she's spun a readable, elegant story out of the case. While we may not ever be able to know whether the scenario she lays out is precisely what happened, it seems, as she notes, just as plausible as any other.
Perhaps it would have been worthwhile to add another perspective or two into the mix: Pauline works well, but perhaps including James Melton (Ann's husband) might have been useful too (Vance's vantage point is interesting, but somewhat removed from the actual events at hand). Nonetheless, it's neat to see original historical research brought to bear here and an imaginative reconstruction of what led to the death of Laura Foster and the hanging of Tom Dula.