I recently got A Shadow in The East, and I think the best scenario in it is Danger in Dorwinion. Danger in Dorwinion is a detective-like scenario, where the players have to uncover a secret cult based in Dorwinion. I made a deck for it and it has won every time I've played the scenario.

Gameplay

Éowyn is obviously a quester due to her 4 , but she can also attack with 5 with Herugrim. A good way to use Éowyn with Herugrim is with Snowmane. The downside is that Snowmane is restricted, so if you want to attach Silver Circlet to Éowyn,(for +2 and +2 with Herugrim) forego Snowmane and attach Unexpected Courage to her instead.

Beregond is your main defender because he has 4 and his effect is AMAZING!! He should have Livery of the Tower attached and you should avoid spending his resources so he can use them to cancel damage.

Glorfindel is your primary attacker, but he can quest, too with Light of Valinor.

Northern Tracker is a good card in the case of the staging area becoming clogged with locations. The downside is he susceptible to Side Street. (Grr...)

Lórien Guide is good as well, for her effect. Comitting her and Éowyn consistently explores the active location.

West Road Traveller is good for her effect, because some of the travel effects are nasty.

The Riddermark's Finest is good for the same reason as Northern Tracker, for location clogs. It can also help out with the active location. (Once Secret Cultist was attached to The Riddermark's Finest and I was like "How can a horse be part of a cult? It's a horse!"

A Test of Will helps with nasty treacheries.

Desperate Defense is good for an enemy with Evidence of the Cult attached while Submit or Die is the active plot. This might sound selective to an improbable scenario but it often happens to me.

Hope you enjoy. open to suggestions.