About finding the dungeon in the N. Wilderness. It is the hardest of the three to activate because the runes are so spread out. One is on the tree on the island in the middle of that shallow pond. Two more are on trees as you make your way west and then three of them are in a semi-circle on trees near the ruins where you fought the robbers and regained the diamond stolen from the bank in Arnika.I know that isn't a whole lot of help so let me point you to http://www.tk421.net/wizardry/wizardry.shtml where you can navigate down to the Wiz 8 Rune Puzzle page. I'd give you the actual page link except it's set to automatically put you back into the frameset if you load the page directly. Anyway, on the Rune Puzzle page there are screenshots so you can see where you need to search for trees. The one thing that isn't made completely clear on the description is that the runes are on trees but you have to use the short staff on a rock/well. The mushroom ring will appear slightly to the west of where you use the staff and N/NW of the stone ruins.
Hope that helps and good luck!