Easy way (without any sneaking): 4) Teleport the whole party to the second portal in the mine. 5) Follow the southern way to the east.
This way you never have to sneak once.
I found it very hard to make the way over the trapped area with the hole Party. They are to slow to reach the way without been seeing the knigths. I go only with my ranger, kill the one enemy group there, flee (make the way back to the portal) and then again and again, until all enemies dead and the ranger is reaching the door ... I was suprised that the hole Party was automaticly teleported there, after my ranger reach the last fight.
If you are sneaking you don't need to go fast over the mines, the death knights field of detection doesn't stretch that far. I did it with my whole party and I never put any points into sneak.
