How do you get pack horse? Are they just normal horses from horse merchant? If so then how do you make them carry stuff for you? I never knew you can have pack horses in this game; the inventory limit as been a pain for me, especially since I like trading a lot and I don't have spare points for inventory management.
This is one of the best guide I have seen, btw, especially because you listed the "cheap" buy range of those items. In general no matter where you are if you know that item is in a cheap buy range, buying them and keeping them in stock will eventually yield yourself profits, more or less, considering that you are not just doing trades but also actively doing quests/killing bandits at the same time.