At least one person must have completed The Everling Lockets access quest in order to to open all the doors to get to Lord Everling. You can do the access quest on your way to Everling while you're there.
Go to Nektulos Forest and swim upstream in the Torrent river until you reach ( 465, -3, -1289 ) /waypoint 465, -3, -1289, a bend in the river south of the falls - make sure you swim in the center of the torrent. Can also be updated at the entrance to Commonlands, near the bridge ( -185, -2, 136 ) /waypoint -185, -2, 136 -- Another update location is ( -212, -3, -668 ) /waypoint -212, -3, -668 which is just west of the Wizard Spires.
Go to the ocean on the north side of the The Commonlands and swim unil you reach ( -858, -199, -987 ) /waypoint -858.43, -198.53, -986.63, a dragon skeleton at the bottom of the ocean.
Go back to The Thundering Steppes, to the west coast, and swim past the sirens to ( 1647, -44, 128 ) /waypoint 1647, -44, 128. Look for the front of the ship and go to the part near the broken stairs. When you get close an enraged octopus will try to eat you. You will pass sirens. If you pass the wraiths, you've gone too far.
Note: It is not necessary to kill the octopus.
Next you must kill Maltus Everling in Nektropos Castle. Lord Everling is level 36^^^ heroic. You only get one shot at Maltus Everling, if you fail he will lock the door and you will have to restart instance for another attempt.
In the Ruins of Varsoon you need to find and kill Hrath T'vol ( 294, 0, 61 ) /waypoint 294, 0, 61, who is level 32^^^ heroic in the Sorcerer's Workshop.
NOTE: He is in the side room to the left. When you go near to the side room he will charge you and start attacking - make sure you clear the main room FIRST! This room is also a three stage ring event, be ready.
Return to Kerath McMarrin.
Next you will go to find and kill Captain Krieger in Thundering Steppes at ( -129, -25, -1047 ) /waypoint -129, -25, -1047, who is level 33^^^ heroic.
NOTE: He does not show up as hostile, however, when you approach he will start attacking.