If you're summoner, you can basically just kill the mobs on the first floor of the house (the one's in the butler's room, and the other's in the Lord's Room) and just not even bother with the ones on the second floor and in the basement.
You'll want to kill the mentioned mobs with your pet one at a time (since they apparently won't group on you if you do it this way).
You'll want to have invisibility on at all times (this won't keep you from interacting with the ghosts, but none of the mobs will see you).
When you get to the last part in the attic, you'll want to just keep invis on, and do the "ward the undead" thing until you're done (will take about 10 mins, so you'll have to run back downstairs half way through and recast your spell to avoid getting attacked).
Edit:
Oh, and thanks SOE for damned near giving me a heartattack when your "boo" zombie jumped up at me right when I was about to kill him. I'm already zombie-phobic as it is. >_<
Edited, Fri Oct 21 13:40:43 2005 by americangeiko