Since I have the book in front of me:
Blessed - infused with holy power
Brave - native american warrior with innate connection to the spirit world
Gunslinger - "devil with a shooting-iron"
Huckster - card-shuffling magician
Mad Scientist - his infernal inventions of steam and steel may spell a new hope for humanity ... or doom it!
Maverick - rogue-like Jack-of-all-trades
Rowdy - rough-and-tumble fighters on the frontier
Scout - stealthy wilderness warrior
Shaman - drawing on the favor of the spirits
The mad scientist may build all kinds of weird gizmos like flamethrowers, gatling pistols, rocket packs and steam wagons. Many of them powered by "Ghostrock" they share one common aspect: There's always the chance of a rather disastrous malfunction when using these.
As for the setting: It's 1877 and as Shewolf put it "The US Civil War did not end in anything remotely resembling a unified country... ", in fact the Civil War didn't end at all!
(The break from our history occurred at Gettyburg, when, amidst the heavy fighting, the dead on battlefield suddenly rose.)
So the USA and the CSA remain, still fighting, at least two different native american nations (Coyote Confederation and Sioux Nations) , the independent "State of Deseret" (a mormon nation), the "disputed lands" (Kansas, Oklahoma, Colorado and Utah), the Great Maze (remains of California) and thr independent "City of Lost Angels".
The "Quest" to build a trancontinental Railroad has led to the great Rail Wars. Today six different railroads are left and they still fight tooth and nail while struggling onwards.
The supernatural is indeed an integral part of the setting (undead, monsters of legends, etc.), so if that is a turn-of, you should try Sidewinder (Classic Wild West for D&D 3E) or Sidewinder: Recoiled (D20 Modern) [not out yet].
So if you have any further questions, just ask away, pard!
Folkert