As far as I know, the money for the 225 Riding Skill and the plain Flying Mount is almost guaranteed if you did some Quests and a couple of instance runs between 60 and 70.

I started dualboxind two Draenei, so I don't have that much insight, but my girl started BC with 1k gold and now has 80k experience left to level 70. Currently she has almost 3k gold.
Ok, there is a trick to this: she has the obviously existing "booby bonus" when it comes to greed rolls. After 2 years of playing WoW i have never won a single roll against her, which also caused some serious fights, because she would never pass for an item, if I was already the highest roller, when only her roll was left.

Anyways, it's no problem to accumulate the 900 (·90%) Gold for the first flying mount until level 70.