This is just what i see from looking at photos and videos, but the Terra has a clear deliniation between the cab and bed which is like a typical pickup truck that you could remove the bed seperate from the cab. Theoretically we could remove the factory bed and install a flatbed or service body...
The rear window is confirmed to be able to be retracted, this will give some access to the cab for HVAC while camping.
I would not expect there to be a mid gate option, that would require a unibody construction and from what I can tell, the cab and bed are seperate.