Ok, but my post is now MIA! I'll rewrite it.
I have a problem with the scale. I know that the travel, by boat, from Adrulia to Zathyra is 1 day long. How many kilometers can a boat do on a river, following the river's flow?
Slightly off topic: how boat are made to travel on rivers? I now have a 50m long boat with no sails, just 50 undead in the lower deck rowing. Can boat use sails? How much the speed change between going against the current and following it?
I also know that the voyage from Gronduk to Camertium is a 7 day trip using horses, but that can actually change (i put it that way for storytelling matters).