Fastest leveling method(from my own experience - done daily really) is:
-Daily Roulettes - ensuring the Dungeon and Commendation challenge log ones are finished on a class you want/need the EXP for
- Daily hunt bills
- Daily Beast Tribes(only gives 10k EXP after certain levels) - ARR up to 50, HW up to 60, SB to 70
- then highest dungeon you can possibly enter
- FATEs until your queues pop

If none of that catches your fancy, you can always grind Palace of the Dead, but that is up to you.