If you're tired of waiting and finding of albatrosses, which "stupid" people kill anyway and f**k up your achievement, then here is solution.
You can mount up in water (where fatigue zone) starts, get high enough and then simply fly on top of the cliff. You have to be either engineer (glider, parachute), paladin (bubble), mage (slowfall, iceblock, blink), priest (levitate), druid (displacer aka blink) etc. to reduce the fall dmg, else you will die up there and unable to loot chest etc.
Here is 3 locations you can reach with this method:
Attachment 15310
HF and don't give up immediately.