I like Rhosgobel, great theme and a bit different than most quests. Yes i get the blind loss first time, but then i play solo with one deck and i cant remember winning first time on pretty much any quest anyway. Once you played you know whats coming so I cant see why this quest gets marked down on the basis of a blind first play.
I am having a much harder time liking the Hobbit boxes or the Ringmaker cycle and Isengaard with its stupid time counters effects crippling you and taking away any enjoyment of trying to build up your forces, becoming a race not an adventure and a horrible addition to the game. Sadly i am finding that many quests after Dwarrowdelf i have to tweak the rules to enjoy solo play - i think the designers upped the difficulty and forgot solo players after the first two cycles. I know they have an easy level but this removes cards you want to play against, far better would have been to have some alternative rules for solo play in each pack. I have managed to tweak some quests to make them play better solo, largely say by ignoring any time triggers which still keeps the difficultly high enough for me.
A good example is a quest i really like - Ruins of Beleghost, but this is insanely hard to solo with one deck too. The Stalking the Ruins Card which adds resources until you complete a quest really for solo should have been a time card which resets after every 3 counters bringing the dragon into play for one round and then disappearing. I guess its easier with 4 players as you can share the dragon around while he is play. This is an example that i think should have specifically been written into the rules of the scenario - do x for multi deck play but y for solo - i dont find it too hard to work out what makes a better rule so i cant see why the designers paid for this cant do a bit better at broadening the game ideas and make the solo gameplay more solid. Rant over - this quest once tweaked a bit is one of my favourites for artwork, monsters and theme.
I think you're underestimating the impact of the encounter deck being able to combo with itself when you reveal multiple cards each round if you think you'd have an easier time multiplayer than solo.