The Alliance has some latitude on where to level once they reach level 12. Quests can be taken and completed in Westfall, Lakeshire, and Redridge. Joan's Alliance Leveling Guide does an excellent job of providing guidance on the quickest path to go from 13-20. Joan starts in Westfall and goes all the way to the Deadmines with detailed info on the quests in between.
Another option is Zygor's Alliance Leveling Guide. Zygor can show you how to go from 1-80 in 7 game days which is pretty cool. Considering he did it without hacks or cheating, and it's even more impressive. It's by far the best step-by-step guide available for leveling an Alliance character. The catch? It's $50.
