Preface - I haven't played WoW for any length of time since quitting at the end of WotLK. I dabbled in the next few expansions, where it seemed gold was overabundant, not sure if that's what killed the gold farmers/gold bots/sellers, but I didn't seem to see any, or even think I might have a use for them. However, with WoW Classic, I can see a market for them to come back. Did Blizz ever put something in the game to eliminate this after WotLK, or was it the gold abundance that destroyed their market. If not, I see the gold sellers and websites coming back.
You will have to talk with flight masters in most towns or cities you visit in order to gain access to that settlement's flight path. Flight masters who have a stop you have not yet unlocked will have a green displayed above their head (and on the mini map), much like a NPC with a quest. Unlocking flight paths as you progress through various zones will allow you to pay for a quick ride to a destination you have previously visited. This method of travel is significantly faster than walking or riding a mount.
Step-by-step class guides are on the way!  The 1-12 Mulgore Guide is the first guide to get all the individual class steps.  At the top of the guide, simply select which class you are playing and the page will dynamically update all the steps in the guide for that class (both text and images).  The rest of the guides will be slowly updated overtime to include all the class steps, but you can see how it's going to work with the 1-12 Mulgore.  I want to thank crazyK and his Placeholderguild for helping me out with the individual class content.  They are allowing me to get the 1-60 Alliance guide done while also getting all the class steps done at the same time, so everything can be ready for Classic launch (hopefully).
I am currently working full time on my Vanilla WoW leveling guides.  Soon there will be a 1-60 speed leveling guide for Alliance, along with in-game guide versions available for my members area.  As of right now, there is no members area, but if you would like to show support for my efforts into this project, you can simply donate to me via Patreon if you like (you will get some cool rewards in return).  Or you can donate directly with PayPal if you like.  All donations are highly appreciated and they will only motivate me more to continue making the best vanilla WoW leveling guides on the web.