It's set in about 1900 on Percival Lowell's Mars after H.G. Wells' Martian invasion of England. A horrific civil war has wiped out the (sentient) Martians, and human pioneers are homesteading, mining, and looting the planet. It's told from the point of view of the Surveyor of Mars (the working title right now), a young man who emigrated because of troubles back home in Montana that led to his father's death. Unfortunately, troubles arise on Mars, too, and a war is brewing between the Company and the settlers...
Gunfighters, Buffalo Soldiers, pioneers, a habitable Mars that never was but could have been: I plan to work more within this setting! By the way, my icon for this post comes from Anoniadi's map of Mars as he and Lowell saw it circa the time of this story.
Inspiration came from re-reading Wells' War of the Worlds (naturally), reading Percival Lowell's Mars as the Abode of Life and Mars and Its Canals to get a feel for how people thought of Mars at the time, and reading Jonathan Raban's Bad Land, a wonderful look at the plight of the pioneers who settled northeast Montana, aka "The Great American Desert." Interestingly, my doctor (getting a checkup today, handily while I have the flu) asked about the book and said that his father grew up right where my main character lived (in Montana, not Mars). Here's a shot of some of my research and notes, including my new (Borders closeout-priced) Sony Reader ebook device, which shows a page of Lowell's Mars as the Abode of Life (1908).
Getting some final feedback from a few readers now, then off it goes to the editor tomorrow!