My best recomendation would be to just camp your character on the stairs before you go to bed. When you wake up in the morning log in before going to work/school. I've killed the priest 3 times and neither of those 3 times did I "camp it".

Chances are some late night unrest EXP group will be clearing that PH over and over again until the priest spwans but they won't be able to kill it. Leaving the priest sitting there during the off-peak hours.

One of those three times It took me 3 mornings to find the priest up but the other 2 times it was just sitting there waiting for me.

Good luck to you!

finally got him