Yeah dude I understand, Id be doing the same thing.
The great barrows boss (not the chapter 11 boss tho) is slightly harder than the Retake Weathertop boss, though he is freaking hard as well and you gotta beat a 13,000 hp "pet" AFTER you take down the 9,000 troll with NO time to heal. Yeah bet you didnt know that , hahah, fucking hard man. I did it but my group were some really good players.
Injate i dont know why it would be grey. You did all of Candaith's other quests?