Hi Dave,
The currently available version of the NS/CR SW1500 pack from EdsTrains does not have a rear-facing view in the cab, and I can find no way to get 4 views in MSTS!

I have modified the left view to give a rearward view, but without the surrounding bodywork (ie windows and door).

It should be possible to create a separate reverse cabview file (*_rv.cvf) which could then be implemented using <Ctrl+E> but, unfortunately, it's outside my current level of expertise! Of course, as this is Open Rails, a 3D cabview would be the answer!!