In the outside area of Threnal there are 3 mini dungeons. Unlike the side lairs in most explorer zones (places like the orc prison and bandit lair in cerulean hills for example), these are actual quests with an entry window, different diffculty settings etc. Yet they currently give no favor rewards and as there's no named items that drop in them there is little incentive to bother with them. My suggestion is to give them a favor reward each, say 2/4/6 of either House P or D favor. They should also appear in the list of quests in the Adventure Compendium.