Gate of the Setting Sun: Gold

Completing these Gold achievements rewards a teleport spell so you can quickly get to the instance when ever you want. These spells are fly-out spells, meaning they are grouped and only take one actionbar slot -that's nice. The fly-out group consists of:

[spell=131204]

Temple of the Jade Serpent: Gold

[spell=131205]

Stormstout Brewery: Gold

[spell=131206]

Shado-Pan Monastery: Gold

[spell=131222]

Mogu'shan Palace: Gold

→

[spell=131225]

Gate of the Setting Sun: Gold

[spell=131231]

Scarlet Halls: Gold

[spell=131229]

Scarlet Monastery: Gold

[spell=131232]

Scholomance: Gold

[spell=131228]

Siege of Niuzao Temple: Gold

The complete list (in case this gets outdated) of Gold dungeon challenge achievements can be found here.

Also, if you ever wonder what heroics you have yet to complete and unlock challenge mode for, simply paste this into the chat on your character:
/run for x,i in ipairs({6456,6470,6756,6758,6759,6760,6761,6762,6763})do local _,_,_,c,_,_,_,_,_,_,_,_,m,b=GetAchievementInfo(i)print(x,"\124cff"..(m and"00ff00C"or"ff0000Inc").."ompleted\124r",GetAchievementLink(i))end



Path of the... lands you in/at... in or near...

Black Ox Townlong: 36, 84 Isle of Thunder
MoP Valor/Justice QM
MoP Zandalari

Necromancer W Plaguelands: 70, 75

Scarlet Mitre/ Trisfal: 85, 30 Scarlet Monastery
Scarlet Blade

Setting Sun Vale: 16, 77 MoP Honor/Conquest QM

Mogu King Vale: 80, 34 MoP players' hubs
MoP Archaelogy QM

Shado-Pan Kun-lai: 37, 49

Stout Brew Valley: 36, 66 Halfhill Farms

Jade Serpent Jade Forest: 56, 58