Kara is easy to get to, its in the zone called deadwind pass that seperates duskwood and swamp of sorrows. But just like onyxia, where even though you can walk over to the instance and have someon open the gate for you you cannot enter the instance without doing the atunement. The attrunement starts with the NPC outside the gate and involves collecting some crap from the ghosts nearby, an item you get after killing the last boss in black morass (requires completion of Old Hillsbrad:durnhold keep in caverns of time), a shard stone from archatrz (tempest keep instances) (requiring a flying mount to get to), a shard stone in shadow labs, and a shard stone in steamvaults. The full quest line for attunement to kara can be found here. http://www.wowwiki.com/The_Master%27s_Key/In-DepthQuote:
Originally Posted by Squiggoth
The plus side is aside from the first part where you must collect shards the items are lootable/doable by all party members at once.