You don’t need TK to get through Corlagon’s Estate, but the road through the dungeon is complex and requires a fair amount to-ing and fro-ing. The reason for this is that you have a number of buttons to push in the correct sequence, and they are in widely separated locations.
Enter the dungeon, go to the back of the entrance hall, and turn right at the T-junction, going east. Enter the room you will find there, and leave it via the door in the north wall. Enter the room you will find at the end of the corridor, and leave through the door in the east wall. Follow the corridor through 2 left turns (you should now be travelling west) and turn right at the first intersection. Follow the passageway as it turns right, and enter a room with some trash heaps in it. Leave that room via the door in the east wall, and follow the corridor through 2 right-hand turns until you come to a door. (I would recommend that you save your game at this point – you’ll find out why when you open the door.) You enter a large room to go along a narrow walkway high above the cavern floor below, and a second recommendation is that your party does not fall off the walkway! (This is where you find that inaccessible chest which you need TK to get at.) Follow the walkway through two left-hand turns, and enter a corridor. Shortly after it turns right you go through a teleporter, but all it does is send you to the end of the corridor, which is where you want to be anyway. Follow the corridor to the end (you can safely ignore all the side-passages unless you want to clear the place out) through a series of turns to a door . You should now be facing north. Go through the door, and leave it through a door in the west wall. Passing through this door leads you into a very short corridor with a left-hand turn in it, taking you to a final room where you press Button 1 on the south wall. This opens a door giving you access to the second half of the dungeon. I hope you remembered all that, because you now have to go right the way back to that T-junction at the back of the entrance hall.
Where you turned right to go east at the T-junction at the rear of the entrance hall, you now go west through a door into a room. Leave the room via the door in the north wall (this is the door that pressing button 1 unlocks), and follow the corridor you find to its end via a whole series of left-hand turns – I lost count of how many but there’s certainly more than 8. You end up at a door; open it, and jump into the well in the room you will find. It’s not deep enough to hurt you. Click on the west wall to open it and enter a corridor which soon turns right to go north, and later turns right again to go east. Look for a short cul-de-sac on your left; enter it, and press the button at the end. (This drops a low wall elsewhere in the dungeon so you can reach another button – Button 3, the one you’d otherwise need TK to press).
Go south to leave the cul-de-sac, and turn left to continue east, the way you were going before. There is a T-junction at the end of this section of corridor, where you turn left. (Turning right takes you eventually to the big room with the U-shaped walkway in a the air above you, which you traversed earlier – you can clear it out if you feel like it, but it’s not essential). This leads you via 2 right-hand turns to a corridor running south. Following it leads you to a room where you’ve been before, leave it via the opened door in the west wall, and you find yourself at the T-junction at the rear of the entrance hall again. Follow exactly the same route you followed for button 2 until you reach the room with the well. This time, you don’t jump down the well, but instead, you turn left and leave via a door in the south. Follow the passageway south, but take a short diversion up a cul-de-sac on your right to press button 3. This opens the passageway to Corlagon’s Lair, nearly the last room in the game.
Leave the cul-de-sac and continue heading south to an oval room at the end of the corridor. Turn left and leave the oval room via the door in the east wall. Go east along this passageway and take the first turn left up a short corridor into a room, where you press a button (Button 4) on the north wall. (This opens up the exit route from the dungeon so you can leave).
Completing the dungeon
Leave this room by the way you entered, go back south, and turn left to continue east along the corridor you were following before. This corridor turns north to deposit you in a room which has exits on the NW and the NE. Take the NE exit, which is the route to Corlagon’s Lair. (Again, I would recommend you save your game at this point, Power Liches can do a lot to damage very quickly given half a chance). Do what is necessary to clear the Lair, retrace your steps to the room with the 2 northern exits, and this time leave via the NW exit. This will very quickly lead you to the room just east of the by now familiar T-junction at the rear of the entrance hall, from where finding you way out into the open air shouldn’t be a problem.
You will, of course find plenty of undead opposition to cope with, and good luck with that. In the game I’ve got going just at present, I’ve taken the time to get Master Bow for all my party before I started this, and it’s been a lot easier in consequence.