Erani - The key opens the door you try at the base of the western gatehouse tower. With it, you see a square room with arrow slits that face toward where the portculis is. There are a few boxes stacked up within the small room and in the center.There is a ladder that leads up to what looks like a trap door to the second floor.
I check the doorway and immediate surrounds for any sign of a trap. If I do not detect anything, I will step inside out of the rain and wait for my comrades. Otherwise I will wait for the others outside, hoping one of them has a skillset for such things.
OOC:
My perception is +2 and investigation is +3, so apply whichever is appropriate to the roll in the DMs estimation.
Alex slowly and carefully follows Erani inside the gatehouse. He examines the interior, looking for anything that might seem out of place or hinder them opening the gate such as damaged gears or rusted chains.
Alexander you see no mechanism in this room that would raise the portcullis, but you know that usually such things are on upper levels. The ladder in the center of the room leads to the second story of the gate house through a trap door.
The upper floor of the gatehouse is very similar to the lower except for a large wheel with heavy chain attachments is mounted to the south wall and the door exits, presumably to the walls, to the east.
Alexander, all seems to be in working order, but as you examine you notice that the chain connections you see attached to the wheel are mirrored on the opposite side. It is likely that both wheels in both gatehouse second floors will have to be turned in unison to raise the portculis.
Alex will return to the first floor and says, "The mechanism on this side appears to be in working order but we will need to check the other side to make sure it is working order before we can open the portcullis. It will require both sides to be operated in unison."
Anyone who takes Kurt up on his suggestion to check the other tower finds a tower just like the other you have been in. You will need the key to open the doors and you find a working wheel in this tower as well. Working together, it is simple to open the portal, but the large modern doors still have the bar across it that you would have to move before all obstacles are moved from the front entrance to the courtyard.