If you've already cleared the 5.0 MSQ, you have access to the new hunt bills. Do those, the SB ones, and the HW ones, as well as the HW and SB beast tribe quests and that is about 8-10mil exp for about 30min-1 hour's work. Despite being level 70, I had no trouble taking on any of the hunt bill marks, even the level 79 ones.