Tried it twice with a Galadriel, Haldir, Celeborn deck.

Lost the first one, mainly because all three of Nenya cards where on the last five of my deck , thus came out very late and I lost due to higfh threat. Apart from this the quest did not seem that difficult though.

Second attempt with same deck, Nenya came on fifth turn (even while I was exhausting Galadriel each turn to get an extra card) and from then on it was far easier. At a point 6 enemy cards pilled up on staging area but after Gildro with a Burning Brand, the Silvan defender character, Arwen and Orophin came in play, I managed to reduce them from turn to turn and eventually won the quest after destroying Bellach (or whatever his name). It took long though, some 14 turn if I remember well

The Silvan deck (the non Silvan cards were Galadriel Hero, Gildor and Arwen, all other allies were Silvan) played very well, especially the trick to return cards to your hand and trigger responses, did a lot of these.