After weeks of trying with mono sphere decks unsuccessfully, I relented and used a tri-sphere deck and beat this quest (just) first time.
I used Aragorn (Core Set), Eowyn & Denethor.
I think if you're playing solo, Denethor is an auto-include for this quest. It enabled me to "cancel" two "Attercop, Attercop"s
I didn't draw "Henamarth Riversong". He is a devastating combo ally for Denethor in solo play.
I also didn't draw Gandalf.
However, I did draw "The Galadhrim's Greeting" and then used "Dwarven Tomb" to use it again.
I also used "Strider's Path" and "West Road Traveller" to ping "The East Bight" out of being an active location three times which really helped me.
I made a few mistakes along the way and beat the game on round 9 with a threat of 49!!!! (EEEEEEKKKKK!!!)
If I'd drawn an enemy on that last encounter card, I would probably have been toast.
Anyways, I think I built a really good deck of 54 cards. If you want details, let me know!!!!
Happy questing!!!