Do you want me to whip up a map for this encounter? Or are you comfortable playing it more freeform?
The pier is roughly 5 feet wide and is probably about 30 to 40 ft long. The drop to the sandy shore below is about 15 to 20 ft. (I haven't fixed the dimensions in my head quite yet. I would guess the higher numbers re more likely.)
The stone house is attached directly to the left side of pier, close to the cliff wall, and is 15 ft. by 15 ft. It is 20 ft. tall at it's peak.