I really hope we get more, though. Just saying. This whole thing sounds way too fun to just have one book written about it.
As for time periods, even Brandon himself has compared fashion and technology on Scadrial to our own (late Regency/early Victorian for fashion, medieval for most technology). From the use of trains and the "Wild West" whatnot, it seems like Alloy of Law can be compared to anywhere between, I'm guessing, the 1830s to the 1890s, obviously stretching to the end of that spectrum if automobiles really are involved.