The road from Heap to Marzarbol swings around the edge of Pon's southern mountains, so that the distance is four hexes, not three. The terrain between Crow's Nest and Marzarbol is forest and plain, so it is easy enough to carve a road that follows more or less a straight line.
Eventually, we can create roads that will take us to other markets - Adeese, Groat, Basimar and so on - but for now we will only want to create roads that we know will be used in the trade sphere we have developed thus far. Trying to build a single system for the whole world will be impractical and will take more time than most people have - our primary goal is to get prices on the board as soon as possible. When other markets (and references) are added, it may adjust the first prices we create, but as this will be done automatically (as we shall see in good time), we needn't concern ourselves with this right now.
Shipping DistancesWhile it may seem that the best method for determining the difference in prices from place to place would be to calculate the cost of using a wagon to transport a set weight of goods, plus time, plus cost for labor and so on, this would be needlessly fiddling in designing what can be a straightforward methodology.
Consider the 2 references of cattle that we have assigned to the Heap in the Hills. We know that this represents 12,800 cattle. For the sake of the system, we can imagine that these are the cattle that exist around the Heap that are available for sale. Of course, some of these cattle can be sold more than once; so that in our system we can imagine that these cattle can represent many more cattle in terms of sales - and that the sales (and resales) in markets other than Heap are fractions of the local availability adjusted by distance.
The distance between Heap and Marzarbol is, as we've said, 4 hexes. We want to think of this in terms of 4 days travel - and to this 4 days we want to add 1 day for the actual organization of the good (in this case, cattle) in Heap. Thus, when considering the availability of cattle in Heap as compared to Marzarbol, we would divide the number of references and the number of cattle by 1 in heap and by 5 in Marzarbol.
For simplicity sake, we'll just compare references. There are thus 2 references for cattle in Heap and 0.4 references for cattle in Marzarbol.
Now we want to know how much cattle is available in Crow's Nest. Once again, 4 hexes separate Marzarbol from Crow's Nest - however, the traders in Marzarbol will want to take their cut; and there will be road costs and various other fees that will be incorporated from taking our goods through Marzarbol. Therefore, we will want to add 1 more day in adjustment for travel. This means that while it is only 8 days travel from Heap to Marzarbol, in terms of trade it counts as 10 days. This will give us 0.2 total references for cattle in Crow's Nest. The total references for all three markets is 2.6, more than what we started with (but remember, resales happen).
Now let's look at something that comes from two different places: fish. We have 1 reference for fish coming from Crow's Nest and 1 reference coming from Marzarbol. In addition to that reference, both markets import fish from the other market (the fish may be different species in each town, encouraging an exchange, or it may simply be both markets encouraging supply). We know that the distance between these two markets is 5 hexes (including the organizing day), so each exports 0.2 fish back and forth between them. That makes the total references for both Marzarbol and Crow's Nest to be 1.2.
Using this system, we can make a new table that shows the references for each market adjusted for distance (both raw and manufactured goods), as shown on the right.
We can also compare the amount of references originating in a market and compare it to imports. Crow's Nest (as seen here) produced 8 references but it imports 4 more. Marzarbol produces 15 and imports 3.6. The Heap in the Hills produces 10 and imports 3.8. These slight differences pile up as more and more markets are added to the system.
Our next two steps will be to translate these numbers into actual general prices that can be paid by the players. First, by calculating raw material prices, thereafter by calculating manufactured prices - the steps are different, as the reader will see.
See Trade System