First, I recognize the BR is not a trade or economic simulation, but I find the rules for trade routes in chapter five unconvincing.

Trade routes are to be set up to trade different commodities between provinces. To this end, the 2 provinces must be of different geographical types or of different cultural types.

These restrictions of race and geography too limiting. For example, I can imagine 2 provinces that would both be plains provinces wanting to do trade because one had an abundance of horses and they wanted to trade with a province that had an abundance of cattle.

Furthermore, a difference of geography does not automatically create a demand. I imagine that a dwarven mountain stronghold might not have any use for a coastal province's abundance of fish even though the coastal province greatly desired dwarven metals and stone.

Would it not make sense that cultural difference be changed to a national one? I'm sure one could find goods in Alamie that Avanil might need and vice versa. I see no compelling reason for Avanil merchants to go all the way to Khinasi lands to find something that might be closer to home and cheaper too. Long distance trade routes should be for luxury and very rare items like silk and spices were in the Middle Ages. More mundane goods should be available at short and medium distances.