On the Isle of the Thunder King, continue along the eastern coast until you see StormSea Landing. Continue along the coast line until you see a large viking like ship. Exact coords aren't nessessary, just look at your map until you see a lock. It's right there.
You should see Pterrorwing mobs with 787k health. On the boat, you can use Shadowstep, or the new Talent, Cloak and Dagger to port on the boat.
Congrats, you're now on the stage 4 section of the island.