As a stand alone book, Colorado! is an average enough western from its era, but seven books into a series it certainly feels like it's just replaying the hits from earlier books. Much like in California!, many of the characters have gone to the state in the hopes of finding gold. It brings bad and criminal elements. The virtuous women have their hearts stolen by the strong men, and the promiscuous woman gets trapped in a life of prostitution. It's less fun the second time reading these same stories.
The only character in this book that's really been around since the beginning is Chet Harris, now a wealthy man in business with his Chinese partner who shared his gold strike in California. Lee Blake also returns in this book, but in pretty limited storytelling. (Once a character gets married in these books, the author(s) seem much less interested in telling their story.) We do get some appearances by children of main characters from earlier in the series, including Andy Brentwood who is in the army and Civil War is on the horizon.
For me, the best storyline in this book involved Tracy Foster. Tracy comes to Colorado for gold but soon discovers he's better suited for robbing and killing people. His brother and sister come looking for him, but Tracy has no interest in going back home with them. The local newspaper ends up calling Tracy the "Grey Ghost" due to the color of his scary, lifeless eyes. It was a bit over the top and hokey but I enjoyed it. Less interesting was anything related to Willie De Berg (this book's other villain, who would do the wrong thing at every moment and of course gets a ridiculous comeuppance at the end).
I'm looking forward to seeing how this book deals with the Civil War, which should be starting soon though I don't know how much action we'll see in Nevada! which comes next.