Before anyone asks - yes there are archived copies of old addon versions both on our github repository and on several of the addon sites we use, and these will continue to be available after Cataclysm comes out, so you'll be able to get those old files if you really want them. I'm not going to bother making these more easily accessible unless you give me a very good reason. "I'm on a private server and I need them since we didn't upgrade to Cataclysm" is a BAD reason - and it's illegal.
I found that in most cases, I could pick the zones I liked and skip everything else. It was slower, but I still wasn't forced to do quest zones I hated (and, notably, I skipped the entire Cataclysm expansion's content -- sorry, Thrall.) I did do dungeons, both in group finder and by two-boxing (more on that in a moment as well), but only once for the quests, and mostly to clear what felt like an awfully long slog from 40 to level 80.

Take breaks. Unless you're straight up no-lifing it over a weekend or something, this leveling process is going to take ~40 hours. But any time you do need to step away, log out. That tiny little bit of rested exp is insignificant...but you never know when something might come up and you'll have to leave for a longer period of time than you expected. Better to be logged out and safe(especially with War Mode on) than AFK waiting for a d/c. Plus, you'll need to stretch, eat, shower, and maybe sleep. XD

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The Horde 12-25 (Barrens + Stonetalon Mountains) guide has been rewritten and revamped.  In addition, there has been numerous tweaks to the speedrun route to make things faster and easier to follow.  Also, in case you haven't noticed I am now adding about 40% more info per step and redoing all the images.  Unlike with my previous vanilla guides, I am now giving a brief explanation of where to go and what to do with each step along with any other helpful tips.
I made one for my guildies but its for the Horde leveling process. One tip that goes for both factions is that you dont need to do all 3 zones to hit 120. I did like 1 and than three quarters of another. But once your 120 you need friendly with all 3 of your factions new reps to unlock world quests so make sure you hit at least friendly with all 3 while your leveling.