This is the deck I used to complete the final four adventure packs of the Dwarrowdelf Cycle. When I got to the Watcher in the Water my secrecy deck with Elladan and Elrohir no longer sufficed. As I liked the thematic idea of Arwen joining her brothers to determine the increased orc activity. It is very straight forward and fun to play. I had to do major changes for the Shadow and Flame quest so the final deck list is a bit of a merge between my "standard" deck and the deck for that quest. For shadow and flame, include all the secrecy cards instead of the dunedain cards and the 0 cost tactics events.
Opening hand: You should prioritize to get Elven Light in your opening hand to get the discard for resources/draw engine going. Rivendel blade, Light of Valinor and Erestor are all good starting cards, as is Glorfindel. Elrond's council is always nice as it decreases your threat and allows you to get an extra quest boost. LoV and Rivendell Blade should go on Elladan to allow him to attack every round if able.
WIth Glorfindel or Erestor in your early hand, you know where to direct resources from Arwen's discard ability and you should be able to play them by turn 2-3. Otherwise you should discard a card to play a two-cost ally so you have an emergency blocker for the first rounds. This allows you to quest for 7 which should be enough for some major progress. Both are really good for the Elven Light engine.
You might notice that the deck is very light on tactics and leadership cards that actually cost anything. This is intentional as it allows you to focus these resources on readying Elladan and Elrohir through their abilities. The deck is very straight forwards - quest with a lot of willpower, use elven light to fue discard abilities and draw a ton of cards - what's not to like?