Sorry, but I found the fastest to level 5 toons is as soon as you can enter a instance....do it. Trust me, you will get tired of doing instances. But it is the safest way to level without having to deal with factions. Plus the bonus is you get BLUE items to wear or disenchant. Do not be discouraged if you cant handle the elite mobs. As you level you will get more experienced and know what to do. I finally got to Uldaman and went thru that instance first time and completed it. But was so thoroughly bored with instances that I finally moved to doing quests after that. Carbonite Quest is my personal favoriate AddOn. So at least do instances to lvl 40 then its kinda up to you how you finish to 70.