Re: WtF: Wild West
THere is already a wild west version of Werewolf...Werewolf: the Wild West.
But if you are only going to use NWoD then I would say first play the game "Red Dead Redemption" and then look at the books you want to use.
Frontier Secrets, ghost towns, Tales from the Trail: Mexico, Werewolf the Wild West, and the Werewolf the Wild West Companion Guide are all available for OWoD