An excellent review of Winter of the Metal People appeared in the February 2014 magazine published by the Historical Novel Society. You can read the full review.
The review concludes by saying: "Herrick fully enters the minds of his historical Spanish and Puebloan characters, showing the cultural and religious differences between the two cultures that would inevitably lead to the first Indian war. ... His research is well founded, and what results is a balanced novel that expresses the worldviews of both sides and relates it in an exciting and interesting manner. This novel is highly recommended for those interested in the history of the American Southwest and its peoples."