Alternative leveling methods

I have 4 level 80 characters in World of Warcraft, and I deliberately played them in a way to experience the maximum amount of content, e.g. making the 4th one Alliance to play through Alliance-only quests. While I don't have the achievements to prove it (achievements are character-specific, not account-specific), I'm pretty certain I did 99+% of the quests in World of Warcraft. So for my 5th character to level I experimented with alternative leveling methods, which would not be based on questin

World of Warkraft...