For most Multi-Boxers, this addon (below) is of ZERO use until level 60 because of the RAF bonus. By the time you have "followed" 1/2 the guide, all of the quests that you still need to turn in are grey (trust me, I tried it). But AFTER 60, or after the RAF expires... the WoW-Pro addon is amazingly fast.

Get the WoW-Pro Quest Addon (built to work with TourGuide). Make sure that you get all of the associated addons (there are 3)... and make sure that you turn QuestHelper OFF (garbage-ass addon anyway).

I didn't do "everything" that they recommend in this guide (they say to stay in Outland until 70... I went to Howling Fjord as soon as I dinged 68...). To give an example of how "complete" these guides are... I averaged < 9 hours /played per level from 70-80, I got the achievements for Howling Fjord (I Toured the Fjord), Borean Tundra (Nothin' Boring about Borean), Dragonblight (The Might of Dragonblight), and Grizzly Hills (For Shizzle my Grizzle)... and it took me TWO quests in Zul Drak (sp?) to ding 80.

I did run a few instances in-between (i.e. going through normal UK, normal Nexus, normal Azerjol) to get those quest-turnins... but other than that... ZERO instance-boosting. Fastest way to 80 = follow these guides.

(Note: Using this guide through outland, I only did Hellfire / Zangramarsh / Terrokar / Nagrand... never even SAW the other zones until I was an 80... doing the summer festival).