Back again. I have posted my efforts as three images: wall (length of corridor), deck (looking down at floor), and corridor (looking straight down corridor to the end). The alignment is close but not perfect, e.g., the trapezoidal arch at the end is not quite perpendicular to the wall. The big problem I had was the right hand wall in the image. It would NOT go parallel with the corridor wall and allow everything else to be at right angles. I also did a view of the ceiling. Those cross members are perdicular as well (or close anyway).
Here are my photos, linked from a folder on my website (I sure hope this works):