I had this crazy idea to try the quest Massing at Osgiliath in solo, since I didn't have anyone to do it with me. The result? I beat it 2 out of 3. I must admit that I was suprise by this result.
I use a Rohan deck with Eowyn, Theodred and Dunhere. Like most rohan deck, my tactic was to lower my threat and to attack the ennemy directly in the staging area with Dunhere (boosted with some dunedain mark).
A big asset in my deck was the fact that I use ride to ruin and The riddermak's finest to remove location in the staging area without having to actualy travel there. My biggest suprise was the card astonishing speed which allowed me to bypass the Lich King special ability.