OVERVIEW - Public opinion is that Passage through Mirkwood is an easy quest. However, I have found that in solo with only the core set, bad things can happen fast. None of my decks seemed overly reliable until this one. It's pretty obvious that Beravor and Eowyn are the best 2 heroes in the core set, but which hero compliments them most against this particular quest? Gloin!
One can potentially rush this quest, but the 2 big baddies make for a bit of a crap shoot. Forest Snare is the ticket, but it's tough to potentially pay for 2 of them. Never fear, this deck has an answer for everything the encounter deck can throw at you here.
HEROES
Beravor - use her card draw ability every round; attach Steward of Gondor in order to pay for the expensive cards; also attach an Unexpected Courage
Eowyn - attach Celebrian's Stone and quest; use her ability to avoid threat bumps and to avoid failing quests or to explore locations
Gloin - attach Protector of Lorien, Self Preservation and 2X Unexpected Courage; he's your defender in this quest and can gain mad resources against Forest Spiders and the like
STRATEGY
ROUND ONE - mulligan for Steward of Gondor unless the opening hand is full of immediately useful cards; use Beravor to draw 2 cards; quest with Eowyn; travel to Old Forest Road to ready Beravor; defend Spider w Gloin and gain some nice resources; Beravor can hold off a second Forest Spider or Dol Guldur Orcs
SNEAK ATTACK / GANDALF - he is pretty much exclusively used for combat round should you get overrun; late in the game, he can take out Ungoliant's Spawn
FOREST SNARE - save for Ungoliant's Spawn and Chieftain Ufthak; plenty of chump blockers to take their attack after they engage
CARD DRAW - make a bee-line for Steward of Gondor; use Beravor or Valiant Sacrifice to make that happen asap
HEALING - plenty of options and SOG allows for easy resource acceleration
TREACHERIES - use wisdom regarding Necromancer's Reach and Caught in a Web; especially early on
FINAL THOUGHTS - the key to this scenario is to prepare for the combat round; use Gloin to block the small enemies and gain resources; DO NOT wipe out the first couple of small enemies you engage; use them to gain resources via Gloin; by the time your threat gets to levels that allow the bigger enemies to engage you, you'll be set and ready to go