I figured I'd plot the formulas from first post since it's a shitton easier to get a general idea of how things change when you have a graph.
Distance bonus is nice and smooth. Before 60km it's not linear, but after 60km it becomes linear and your bonus is increased by 0.5% per kilometer. There is obviously no maximum, but it's probably not a good idea to carry your goods much farther than 50km or 55km.
The troop cost plot is not smooth since you can't have half troops, but it's even less smooth thanks to rounding up and me using excel to calculate it in 10 troop intervals because excel draws prettier plots than R. We can see it rises up sharper when you have more troops, but it isn't really THAT bad to begin with. It's also interesting to note that it would seem that you can have something like 150 troops at the same price as 101 troops. I can't be arsed to calculate the exact point, but there it is.
I also thought it'd be interesting to see how much you are paying per troop. It looks fairly funky thanks to the flat plateaus of the total army cost graph and just tells what was already noted previously. Sometimes you get more bang for your buck with more troops.