I'd just like to thank everyone who did THK with us last night. Although we were unsuccessful at fully defogging the map or completing the bonus, we did have a lot of fun and we did get some of the obscure parts of the map explored.
For the next time we decide to go exploring in THK, I found this on
Guildwiki.
Strategy C
This strategy begins similarly to strategy B. The party initiates the bonus by lighting the torches, then defends near the king's throne. However, after the initial several waves of attacks, there is a break in the battle. At this point, the entire party heads outside of the gates and proceeds north, ensuring that no creatures were already enroute to the keep from either the east or the west. While heading north, you can safely ignore any Murssat and Jade that are in the Dwarven villages, if any. They are related to the bonus, and if the bonus had been taken they would have been part of one of the first few waves to attack the fort.
All enemies that attack from this point onward spawn in an area to the north of the keep, near the portal that later transports everyone to Ember Light Camp. To reach the keep from the spawn point, all enemies must pass a narrow choke point. The party can station themselves at the choke point, and eliminate all attackers without risking the King engaging any of them. Dorian's party also spawns at this location, and can be eliminated in the same way.
Note: Just below the choke point are two parties of Jade. These can optionally be ignored, or destroy them during breaks in the spawns so that risk of accidentally aggroing them is eliminated.
Note: the portal only works in the cut-scene, walking through it prior to completing the Thunderhead Keep mission will have no effect.