In Port Crag, in the NE building, you can enter a pipe to reach the NW building (there was an agility check, but can't remember whether it was 6 or less (my character has a base agility of 5, so less than 6)
But I can't make the return agility 8 check. I tried to kill everyone outside (too difficult at level 22, even packing them in the SW (detonating TNT behind the Metal beams).
As I spend a two hours killing the pirates in the NW building and exploring the basement, I would want to avoid reloading an older save.
SuNo