Well this is the video mentioned in my Pistol build video. This is by far the fastest method I found. I was killing the dragons, Bunker, Warrior for about 3 hours and got to 68. I went from there to 72 in about an hour. So only a fraction of the time. I hope this helps you level up quicker. Below is another video a friend of mine did. He actually shows some numbers to prove what its actually worth. Go check it out and Thanks for Watching!!!!
Friends Ranking up video:http://www.youtube.com/watch?v=8VR5GtklgNA