These are the final mod's and some closeup and test fit. It's pretty much done other than either extending the serial data line or slicing into the cab floor and installing a "roof" panel to tie left and right hand sides together once the floor is cut. There is room and that might make installation of the cab easier since there would be more surface area to grab. Lionel had the cab interior mounted to the frame which is why the "U" is on the bottom.
Comparison of an un modified cab with a modified one. I cut out the back panel so you can see across the cab.
Close up of finished cab looking forward and rearward
Looking across the cab
Engineer in cab
Saws used to make mods. These are just various "razor"/"snap" saws. The top one is flexible and called a "flush cut". I used that to remove the mounting pins/stanchions on the bottom of the inserts. The bottom one is "shorty" that allowed me to slice open the plug between the engineer and fireman's side of the cab.