Instructions
Travel to Tenpenny Tower.
Speak with Chief Gustavo.
Travel to Warrington Tunnels, located to the southwest of Tenpenny Tower.
Find the door to Roy Phillips' hideout.
Choose whether you want to side with the ghouls or Roy. If you side with the ghouls and kill Roy, the ghouls will move into Tenpenny Tower without killing the residents. If you side with Roy and kill the ghouls, Roy's gang will ultimately wipe out the current residents of Tenpenny Tower.
Return to the Tower and locate Allistair Tenpenny.
Follow his instructions to allow the ghouls to move into the Tower. This will end the quest.