Not too long into the game, you'll come across your big free-roam area, Croakwood, just after leaving the village, Markovna. In this area, you'll find both a Merchant with an escort quest, and a camp. In the picture below, the quest-start/merchant is the red circle, and the green circle is the end point of this quest, the camp.
This is a lot simpler than it sounds. If you go around this pathway/this whole area and wipe out ALL enemies before accepting the quest, they'll stay dead. A new enemy mob SHOULD spawn to the left of the quest giver, but not only did I avoid where they should spawn with my route, I also didn't see them spawn at all, which is a slight bug, but a good one. Just make sure the whole area is clear, escort him there, and get a trophy.