I have just dug my cad package out and did some screen grabs of the layouts.
This one shows the dimensions of the internals of the bus (click on the image to see full size)
The grey area at the bottom right is the drivers area.
This is the layout as it is now (no scale and sizes are just guesstimates)
The box at the top right is the steps down to the door and the box to the left of that is the gas cabinet probably too large for the scale of the drawing.