Shoulder of the Chamberlain?

i just started doing the isle of thunder, and one of the quests i have is called "The Crumbled Chamberlain" i have to gather this person body parts.

I have all of them but their shoulder, it's up on top of some mountain that i can not reach. I did some checking online, and people are saying in need another quest. This quest is called "Skin of the Saurok" just to be able to get up top that mountain.

So i went looking for this quest giver and can't find them, yet i see horde characters zipping past me in Saurok form or whatever it's called.

What the hell is the deal with this quest, why can horde characters find this npc and i can not? The biggest question i have, is why the hell is one quest completely reliant on a totally unrelated quest?

Also, what is with this stage 5 i see on my map and referenced on wowhead, what is the purpose of it?

I hope this zone is worth it, because so far it's completely annoying, having to fight something every few feet.