Valley of the Four Winds

It is faster to complete the LFG one and the Tour one. For LFG, you need 2 things completed (as opposed to Jade Forest's 3). For Tour, you only need one treasure (compared to Jade Forest's two or three) and three rares, and this is a slightly more dense zone than Jade Forest.

Notable rewards for the [event=1496] event:

Mount form Time Trial Achievement:
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[item=220766]

Toys from Infinite Power XII Achievement:
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[item=217723]
[item=217724]
[item=217725]
[item=217726]

Items from Zone Achievement:
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Townlong Steppes = [item=221817]
The Jade Forest = [item=220777]
Valley of the Four Winds = [item=221816]
Krasarang Wilds = [item=210334]
Kun-Lai Summit = [item=218247]/ [item=218248]
Dread Wastes = [item=220765]
Vale of Eternal Blossoms = [item=220768]
Landfall = Appearance: Class Ensemble
Isle of Thunder = Appearance: Class Arsenal

30+ New Mounts for [currency=2778]:
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Guide Link

I don't know why you've been downvoted. I just got to this achievement and your advice has been way faster than doing the campaign all over again. Cheers :)