The compressor on the original Lanakila was on the firemans side of the locomotive. The Bachmann was on the Engineers side. I moved the compressor. This was actually the easiest modification to make so I did that before I did any of the steps I described previously.

Using the Bachmann cab I scribed in the cut away for the backhead.

I used the Xerox copies of the Sugar Trains Pictorial photos to determine the size of the cab and it's doors and windows. I have no photos of the back of Lanakila, so the back part will be a best guess.