I originally thought I could wait and do the cab last but I needed to have it done so I could see how everything was going to fit inside it.  I used 15ga (about 1/16") sheet metal for the cab.  I rough cut the side and front then temporarily put it together for fit.

I glued the CAD drawing to the sheet metal and began cutting away.

I welded the sides and front together but connected the bottom floor with screws for easy removal.

I'll make the top later.  Now that I have the cab almost done, I can begin laying out the controls.