During a livestream last night, me and the Card Talk crew finally beat the scenario 3p.
We got lucky though, we had to use 2 players to take on all enemies and I had to rely on a lucky draw for Untroubled by Darkness to quest through to the end. Final encounter card was a Hideous Deeps, which took 3 of the 4 cards left in my player deck. So with 1 card left in my deck and 2 dead players (Mono-Lore VD deck and a Silvan deck) we eventually won. But we wouldn't have made it for another turn, and if that Reek treachery came up, or the Torech Gorgor Patrol, then we would have lost.
The strategy used was to have the mono-Lore deck use high cost Lore cards to deal with the quest, for instance The Great Hunt for the Patrol and Gildor's Counsel to reduce the encounter cards per round. Haldir+Legacy Blade helped out with ranged attacks to kill Werewolves and Spiders. Dwarves had to rely on Untroubled by Darkness and Dain Ironfoot to quest hard whenever we could. We used Naith Guides from the Silvan deck to keep Sulien ready and used Lore resources to use her ability to basically quest double and not be affected by location lock. Dwarves also had a lot of recursion with Dwarf Pipe, To Me O My Kinsfolk, etc. Silvan deck provided additional support with questing and Ranged attacks, but was the first to die. The good thing is that if you know you are going to get decked, you can have that player take the biggest enemies and help the other players as much as possible so that they have an easier time. Including Ered Luin Miners and Hidden Caches is also highly advised! I discarded 3 Hidden Cashes at once, setting me up with enough resources to afford my allies. Ered Luin Miner got discarded for setup, so I started with a free ally, which is nice for the deck to get to 5 Dwarves quickly. Ever My Heart Rises eventually got discarded to a shadow effect, but it was free threat reduction and readying for my Dwarves since all locations are Underground.
All in all, the quest is very brutal, and we won by YOLO-questing on the final turn, with 2 encounter cards that could have cost us the game. But the victory was very sweet in the end (especially since it was 4am for me at the time)
Best of luck with your games everyone. Looking forward to your strategies.