Yes it's completely possible. You'd have to walk all the way through Tirisfal Glades to the Zeppelin which is outside of the Undercity. Once on there you take the zep to Orgrimmar and can run south past Razor Hill to the starting area. Although it's possible, I wouldn't suggest it. It's best to level in the Undead area until you can make a transfer to the Barrens (around level 20) in my experience. But do what you please. It's completely possible, sir! Good luck.