EDIT: I'm rethinking the concept behind this guide. It will probably focus more on quests and less on levelling, so as to be a companion, rather than a competitor (hah! yeah, right) with Jame's guides.
This is a rough draft of a zone-based levelling/questing guide intended for Horde players. The writer of this guide chose Aldor, and there are a few Aldor specific quests included here, but they should be clearly marked. This guide should work for level 63 or 64. I completed most of it solo with a 63 hunter, but other classes may need to wait until 64 for some quests.
I may expand this guide in the future, to include both Zangarmarsh for levels 61-62 (and the start of 63) and Nagrand. Definitely the latter, as I'm finding most of the Bone Wastes too dangerous for 64.