Hoi,
i can't tell you any rules OT for sure, but IT are some points where you can interact with allready established business groups or guilds.
there aren't any special rules i'm aware of, but the guildrules normaly apply to everyone. so it would be awesome when you guys get in contact (should be enough when you go there on conquest) with the traders guild (Handelsgilde) or someone in the baggage (Tross) to offer the tithe/tenth part duty for the horde… äääh, army ^^ the coloss needs money to work, we traders, craftsman and more are there to get the money rolling and pay our due…
different rules for different streets and parts of the baggage should be learned on-site, it's more fun that way ^^
you are traveling traders, so you are used to different rulesets, right?