I tell you my experience. I'm leveling a priest that it's 60 now and since I have also done some instances (and I have full heirloom set with 20% experience gain bonuses) and been very ahead of the guide, I skipped some zones since they were grey quest for me, well it was a real mess. Missing quests because I didn't to the previous to enable the following. Going in a zone then realizing that I couldn't do that quest because I didn't do the starting quest chain, very unconmfortable. In short what I suggest you it's not to skip areas, or make really sure that you do all the quests required (at least) and check carefully the previous zone you'll going to skip to make sure that you won't have problems with struggling finding where to start the quest chain to sync with the guide section.
There are several reasons why this may have happened. First, only a fraction of the players who interact with the auction house buy or sell WoW Tokens. While the value of both gold and commodities plunged relative to real money, the value of gold and commodities remained steady relative to each other. Players who didn’t interact with the Token market could buy the same number of flasks by doing the same amount of world quests, or selling the same number of gems or enchantments, so these sellers saw no reason to raise their prices.

The older brother of this potion originally came about in Cataclysm as the Potion of Treasure Finding, and is actually one of the best ways to make money. Since most Pandaria mats are constantly farmed, they usually sell for less than the Cataclysm mats. This makes using this form of the potion more effective for making gold. Not to mention that creatures die faster to level 90s since they were made for the previous expansion, making farming the treasure chests that drop rather easy.
Leveling from 58-80: Outland and Northrend Recommended leveling paths for level 60-80 players in WoW. Includes best zones in Outland and Northrend, as well as notable quests and rewards. Leveling from 80-90: Cataclysm and Mists of Pandaria Recommended leveling paths for level 80-90 players in WoW. Includes best zones in Cataclysm and Mists of Pandaria, as well as notable quests and rewards. Leveling from 100-110 in Legion How to level quickly in World of Warcraft Legion from 100 to 110. Includes heirlooms, assaults, useful items, and experience boosts. The Big Bag Guide This guide covers bags from drops, quests rewards, vendors, and professions. Additionally it also covers item type specific containers.