How to reach Dragon Necropolis
Find a Druid or Wizard that can port you to Cobalt Scar or make/join a guild for Guild Hall access and come to Cobalt Scar that way instead. Once in Cobalt Scar you're going to want to travel all the way up to the northwest corner where you'll find an underwater tunnel that leads to Siren's Grotto.
Once inside Siren's Grotto - if you're a class with a way to evacuate/succor DO IT!! This will put you on the otherside of the zone by the Western Wastes zone line. If you don't have any way to evac then you're stuck having to run through the zone the old fashion way =( . Use my map below for guidance.
After you're through Siren's Grotto and you pop out in Western Wastes head to the northwest and you'll come across Dragon Necropolis inside the first large crater (scar) that you come across. If you need help finding the location use the map below for some extra guidance.