1. Progress to this quest in deepholm: The Stone March Quest: The Stone March
2. Go to the questing location:
3. Farm all the mobs in this area and pass them by Boden the Imposing. He does AOE and will 1-2 shot most mobs.
The mobs that spawn are twilight soul reapers and defaced earth ragers. They give you FULL XP despite having NPC Help. They also have low health and die pretty quickly. They are on a VERY short spawn time. Not instant. But Very Very short. They also have a regular loot table, so you can put it on auto loot and get gold and items while you are grinding these mobs.
I was getting about 1 bar every 30 mins or around 1 Mil XP an hour + gold at level 84 On NON RESTED.
Still working after the last restart.