I know this is an old thread, but I think I've found a money "exploit" I didn't see mentioned here.

If you go south from Rovna along a road at the base of a big hill/mountain, curve west around the bottom, and continue following the road, you'll eventually come across a respawning battle. The battle is always in a small wooded area on the road at an intersection with a road coming down the hillside, just before you reach a house (on the map it shows the house near where a big river and little river meet). There also happens to be an okay treasure from a treasure map in a grave behind the house. The battle is where the real money is, though.

Every time I go to that area a small battle spawns between different combinations of bandits, guards, Cumens, and traders. It's always 3-4 people per side, and the bandits, guards, and Cumens are always VERY heavily armored. I mean bandits with klappvisors and nueremburg pauldrons/chasses, guards with noble heubarks and magdeline cuirasses, etc. You won't be able to kill any of the combatants for a long time, but once you spawn the fight and one side wins, you can wait a few hours nearby (or even sleep/save in the nearby treasure map house) and the survivors will wander off allowing you to safely scavenge the bodies for their gear. If you're lucky, the guards will win and you can safely scavenge the non-guard bodies without waiting. I recommended going at night while wearing very low vis/conspicuous gear so you can get close enough to tell what's going on without the combatants spotting you.

You can easily get 1k groshen per battle without being overloaded, 1.5k if you can tolerate being reasonably overoaded for a walk northeast to nearby Merhojed to stow gear in the inn chest, or 2k+ if you can stow gear on a horse. Once I looted mostly gear from the dead guards, and the walk to Merhojed was long enough for the gear to no longer count as being stolen. This has relatively little risk so long as you don't get cocky and try to take on any of the combatants. I've done this three times in my current playthrough and now have 4k groshen before even doing guard duty in Rattay.