So the Carrock is immune to player card effects, which means it can't be taken out by Northern Trackers, Lorien guides, travelled to with Strider's path etc.
Once you have travelled to it (as a result of questing) what happens with Legolas?
Is he a player card (or are heroes a separate category)?
If progress tokens for him killing an enemy CAN'T be added to the Carrock, do they go onto the quest instead? or is his ability just redundant?
About to have a first play of this in a few minutes - I'm guessing it would help to have Legolas place the last token on quest card 1b, so that there's at least a chance to quest against the Carrock before fighting the trolls, although with 10+ threat automatically in the staging area, it doesn't sound particularly easy to make much progress on it...