I do not recommend going for TBC, although I remember Hellfire peninsula to be decent, everything else is rather slow. Instead go for WotLK, Borean Thundra gets you levelled very fast, and then you can head straight for Icecrown at 67, which is also insanely fast, although admittedly has a few elite quests. You can go to Sholazar Basin alternatively. 2 zones should get you 60-80 no problem.
Once you reach 575 you can purchase vendor recipes for the last 25 points. The Blacksmithing recipes are on a vendor in Vale of Eternal Blossoms. You can enter Vale of Eternal Blossoms after completing the questA Celestial Experience (requires level 87). After you completed the quest, you can find Jorunga Stonehoof (Horde) in Shrine of Two Moons and Cullen Hammerbrow (Alliance) in Shrine of Seven Stars.
Mag'har orc - "For untold generations, the orc clans of Draenor battled one another in endless war. But when Gul'dan offered them the blood of his demonic masters, the disparate tribes of Mag'har—the orcish word for "uncorrupted"—refused the dark bargain and banded together to drive out the Burning Legion. United under the leadership of Grommash Hellscream, the Mag'har pledged to one day repay Azeroth's heroes for aiding their cause. As war against the Alliance intensifies, the Horde must call upon the might of the Mag'har to seize victory."
This is cumulative, as you take into account each failed sale as a loss. In the event too many deposits accumulate, you must decide whether to continue selling the item inflated by too many sales or finding of another way to dispose of it. One final tip: when you find that an item fails to sell in one AH, selling it on the other may finally dispose of it and get you your earnings.
Now lets get to a "math". You need 10k reputation for a cache. For a daily emissary quest, which gives the rep the fastest way you receive 1.5k reputation. Since the quest needs 4 of the world quests for said faction, lets total them up to 500rep which gives 2k reputation for an emissary cycle. Lets optimistically say that you require 3 minutes to reach a world quest and finish it, totalling at 12minuter per 2k reputation. It would mean that you spend an hour total on a chance to get up to 5k gold. Ofcourse there would be some exceptions to that, such as tortollan quests that need only 3wq, rare quests that give extra rep and more rep in general or for example follower missions for extra rep (but those require resources). But there is also a fact that you might take more than 3 mins to finish a wq which negates that.
Some quests in my guide are marked as "SKIP" and colored in red. These quests are simply either too hard to solo or not worth the XP/time and are skipped. My guide will only list SKIPPED quests if the quest is a direct follow up after completing a quest, not one that you have to click the NPC again to get it. If you hover over the skipped quests, it will give info on why it is skipped in the guide (unless that info is already listed directly in the guide text).
I recommend not counting on transmog sells for your monthly gametime. Its a great market, but also pretty random. You have to have the right items posted at the right moment if a player needs a certain item. If this is not the case, of course you will not sell anything to him. There are people making millions of golds a month with transmog. But they are very professional at it and it really takes a lot of time.