If you want to be real lazy, you can even do a low-profit loop around Seonan Epicrotea and Sturgian country. If you really want to complete the quest you can buy new Aserai horses at $700 a piece and still net 7K. If you need startup capital just do the old “… sure ill deliver that herd of 10 Aserai horses to Bob the Foul Smelling for $350” and then just actually sell them in Vlandia. Just make that route when you need money and stop at towns and cities along the way to check for smithing opportunities, trade opportunities, bandit camps and the occasional You can buy grapes and furs in Vlandia/Battania to sell in the desert place, but the profit margin isn’t that big. Get like 30 wood in Seonan and turn it into charcoal, so that you can smelt tribesman daggers and try to do the smithing orders on the trip.
You can sell the Aserai horses in Sargoth and for 1200-1400, and you can sell desert horses pretty much everywhere for 300-380. Just go to Askar and buy ~ 15 Aserai horses for under 800 and ~50-75 desert horses for under 180. If you want to do an easy 50K trade route… Buying/forging a good mace to knock out lords can get you a lot of money if you’re fighting a lot. Much money and how far in the game are you? If you’re raiding I’ll assume you have some money already and need to make more.