Start quest the doom of wortham act 1.7 (beginn quest)
-talk to the stranger and then pay a visit to the ferryman
-run towards the center of wortham
-kill urzel mordreg
-now the spawning elite pack
-receive your reward teleport back
-now repeat
a run took me about 1:30min quest reward is ~63000xp + mob exp
this then add up to 2.8mio xp an hour