Personally, I would never permanently disable or remove the rear doors. If you are involved in an accident and roll that vehicle, it may land on the right side and block that door. I realize most of you have a pass-thru between the cab and the back, but that is not a guaranteed means of escape either, since it only goes into another part of the vehicle. All living quarters are required to have a least two exits for a reason. Since your vehicle is privately owned and as long as you don't hire it our, you don't have to meet those requirements, however a little common sense goes a long way here.
And what about if you want to upgrade or modify your interior, or even get to some of your systems for repair or replacement, access through the rear doors could be very helpful.
I would just close the rear doors and lock them, making sure they can be opened from the inside without having to use a key or any tools. I taught Vehicle Extrication for 30 years, and I have seen some weird stuff in my career in the Fire Department, so I know how easy entrapment can occur..