[DL] Range Wars/Great Rail Wars

[<markus.finster@chello.at>]

I'm thinking of introducing GRW and/or Range Wars to my gaming group. Now, I've never played miniature games, so I have a few qustions about those:
Is Range Wars played with cards or with miniatures?

How does a GRW-session run? I'm not talking about the specific rules, just a general overview: Is there one player the marshal who, I dunno, introduces twists in the fight? How many can participate in one game? How long does one of these games take to prepare and how long is one gaming session?

Do the GRW-Sourcebooks have any influence on the official timeline? If yes, maybe I'll just buy them to learn more of the world...
Oh yes, are the sourcebooks seperated in posse and marshal territory as well?

And finally: The online shop says that if you buy the core book, you get one starter army for free. Which armies are there and how much do they cost? How many minitaures are in an army? Could you use the cardstock cowboys for GRW as well (scale)? 

Thanks for your help.
Markus