First off, credits to Thomja for the idea of farming in this area. Before people shout repost, this is a refined version of his farming spot that extends out a bit to score the most nodes in the least amount of time.
I have created a map for the best possible farming route that I've discovered so far in the Valley of the Four Winds. Following this path, I've been able to score 32 stacks in 30 minutes with 310 flying as a paladin. YMMV with the frequency of rich spawns; I consider myself fairly lucky. Regardless, this place is just plain ****ing crazy. Be careful in the Kunzen Village, level 90 mobs are a pain there. I skip over the nodes that are surrounded by npcs because it's not efficient to kill them.
Start at the circle.
https://i.imgur.com/zC56C.jpg
THE ANCIENT PANDAREN MINING PICK WILL WORK WONDERS HERE - You will be able to farm gems while mining. I haven't gotten the pick yet but I am going to ASAP.
The black X is a level 90 quest boss non-elite. If you aggro him, be careful, he'll knock you off the mountain if you're not positioned right.
Oh, and try not to aggro the goats. Don't wind up like me and be embarrassed by getting killed by a non-agressive non-elite mob that knocks you off a cliff, then die again because you ressed right before you hit the ground as a ghost.
IF YOU ARE UNDER LEVEL 90 then the Valley won't be AS efficient as a 90 but you can still farm here. The Heartland is insane for Ghost Iron Ore and I was able to hit max mining before I got to 87 in a very short time.
THIS MAP WILL BE EVEN BETTER IF YOU ARE ALSO A HERBALIST.
FAQ
Q. Where do I get the Ancient Pandaren Mining Pick?
A: Greenstone Quarry.
Q: Where the hell is that?
A: Jade Forest, south of the Tian Monastery.
Q: WTF I CANT FIND IT U MORON D:<<<<
A: It's a rarespawn.
Q: Does trillium spawn here?
A: Yup, in Kunzen Village.
Q: Why do people farm so often it sucks
A: Why DON'T you farm?
Q: What the **** is up with your name?
A: Misspelled while renaming. ;-;
Reply with feedback if you want. Hope you appreciate the guide. If this helped you, please at least reply with a thanks. <3