Make sure you do hinterlands!!! I went from 48-51 in about 3 hours. and I was almost 52 or might have even been 52, if not I was very close. It was insane, every quest but 2 was a easy kill or one drop quest. Insane.
Then I did all ungoro kill quests and then WPL and 4 or 5 in EPL and I was 60.