A guy in reddit has posted video guides for all WoD gold modes:
http://www.reddit.com/r/wow/comments/2npojc/wod_challenge_mode_gold_guides_88/
Also of interest, in the comments he gives his opinion of their rank from hardest to easiest:
Auchindoun
Iron Docks
Shadowmoon Burial Grounds
Grimrail Depot
Skyreach
Bloodmaul Slag Mines
Upper Blackrock Spire
The Everbloom