Karazhan Key

You don't need the key to enter Karazhan, someone can always open the door for you, but its still useful to get.

You can start the quest line at 68:
-2 Quests in Deadwind Pass outside Karazhan. They are soloable.
-Talk to some guy in Dalaran of Arathi Highlands.
-First key fragment is in Shadow Labyrinth.
-You then get the quest to go to Coilfang Reservoir and Tempest Keep (need flying mount for TK) for the second and third key fragments.
-Final step is completing Black Morass (you need to have done old hillsbrad to go to black morass)

I'm going to recommend a friend for the Deadwind Pass quests.

i completed BM, but still lack the fragment to get into kara (need to run arc). are you saying after the key quest, you still have to go back to BM? cuz i hate that place.

Yep gotta go back to BM after the fragments.

UPDATED:2.4