There can be only ONE copy of each card!
A while back someone proposed the 'Highlander mode challenge' to me: a deck using maximum one copy of each card by title. Obviously it's highly unreliable, but it can be super fun. I tested this against Nightmare Passage through Mirkwood and came away with 4 wins out of 6 plays.
Basically you're obviously relying on the power of your heroes to carry you through while you draw, with Boromir handling combat, Eowyn handling questing, and Galdor switching between the two as appropriate. Use Galdor's alternate mulligan ability to try and optimise your opening hand towards thign which will immediately help you quest better (willpower allies, Light of Valinor, Unexpected Courage), survive combat (combat allies, damage cancellation, healing, Gondorian Shield, Captain of Gondor) or draw more cards (Daeron's Runes, Deep Knowledge, Elven-light).
Since your draw is really inconsistent, you never know exactly how well the deck is going to play, but then that's the fun of it. And with the inconsistent draw otherwise, you may well get decent use out of Lindir and/or Galdor's second ability.
Additional discussion and play-session report in this blog post: https://wardenofarnor.wordpress.com/2016/03/16/highlander-mode-challenge/
Nice deck! It was also successful for me for PtM Nightmare, despite losing Galdor to Ungoliant's Spawn.