However, for game purposes America has been part of the Anglo-Saxon Empire and largely Anglicised for the last 150 years or so, and the gallant crew get most of their ideas of the romance of the Old West and America filtered through a very British lens.
So... I think that the Firefly crew would work for this, if suitably modified. E.g.
The Reverend Book (strict C of E)
Miss Inara Serra (of the Bombay Serras), a gentlewoman and adventuress
and so forth.
Anyone want to give me versions of River, Mal, Jayne, etc.?