My wife has been playing with the Spirit Legolas/Leadership Gimli throughout the entire Lord of the Rings campaign, and at last the pair have made it to the end of their quest and the footsteps of Mount Doom itself. It is a bit unclear how the pair rejoined Frodo while simultaneously meeting their doom at the Black Gate, but the Valar work in mysterious ways.
Given that this quest appears to heavily punish using allies, a pair of three hunters decks seems like the optimal solution. It is my opinion that this archetype benefits heavily from access to tactics, so this deck bids farewell Berevor and adds Tactics Eowyn, who can also serve a backup defender if she gets Snowmane and a Golden Shield. Elven-light is a key to see early, and Raiment of War helps flip the contract as quickly as possible—it can be replaced with more optimal attachments later. Leadership cards are kept to a minimum to free up Gimli’s cash to ready Legolas—Unlikely Friendship should generally be played on Gimli for this reason.
Gimli has the tireless ranger/forewarned boons.
I’ve tested the deck as-is versus a variety of quests, and it works pretty well—the contract addresses many of the Legolas/Gimli duo’s weaknesses—but without the two boons, Gimli has an unfortunate tendency to die, as his printed defense just isn't up to snuff. Adding in The One Ring, Inner Strength, and either Well-Warned or Favor of the Valar from the sideboard should address this.
This deck, in conjunction with a version of Beorn's Grimbeorn 3 hunters deck, beat Mount Doom with plenty of time to spare. In terms of changes, I would definitely go up to 3x Miruvor and possibly increase the number of willpower attachments. Miruvor in particular is a key card for this quest because not only is the extra ready for fortitude test valuable, adding a point or two of willpower can be key and in fact ended up being the difference between victory and defeat on the final fortitude text.