How to get to Kor-Sha Laboratory
There's two routes you can take to reach Kor-Sha Laboratory; both of them start with your taking a Guild Hall portal to either Lceanium (EoK) or The Overthere (RoS). If you have Ring of Scale then purchase the Miniature Worker's Sledgehammer and give it to the portal tender to be taken to RoS' Overthere. From here run south to Frontier Mountains (it's the picture to the right that's above) and then skip down the page to that part of the guide.
If you don't have Ring of Scale, purchase the Fragment of the Combine Spire to be taken to Lceanium (Picture on the left that's above). From here run northeast to Scorched Woods. You'll zone in at the location displayed in the picture below.
Travel through Scorched Woods to the east until you make it to Frontier Mountains, which is the location shown in the picture below.
Those of you who came from The Overthere will have to run a tad bit south and then east to make it to the Gates of Kor-Sha. Don't worry, barely any enemies see invis in this zone so the run shouldn't be all that dangerous. The same goes for people who enter Frontier Mountains from Scorched Woods, you'll want to invis and run to the northeast.
You can safely run through the middle of the zone so long as you have regular invis on. As far as I know the only enemies in this zone that can see through your invis are the nameds.
In the Gates of Kor-Sha you won't be so lucky with few see invis enemies. Through this zone you'll need to play hopskotch avoiding enemies that see through invis as you work your way up to Kor-Sha Laboratory. As you can see from the map above there's two entrances into Kor-Sha Laboratory.
Blue Line: Enters on the western side of Kor-Sha Laboratory near Overseer Dralgan.
Black Line: Enters on the eastern side of Kor-Sha Laboratory near the Glart Fink.