There is an event that does not appear on your map where you stand near supplies to capture them. This event spawns 4 supply caches that you stand in a ring to capture. Each capture grants you a rep token for both the area faction and your chosen Faction. On the fourth and final capture, a boss will spawn. After he is defeated and the point is capped, a chest will indeed spawn, as it were a normal event. I have seen exotic engram's reward from this chest, and its rather easy for farming tokens. It doesn't have a heroic event trigger as of this moment, but I believe it doesn't at all. Happy Rep Hunting!