Lori - My '78 Bubble is the 1%, being a none walkthrough model.
That's because it has twin sliding doors. It started life as
a twin door panel van. A few of these vans were converted
to buses by some company over here (because they had two doors)
by cutting holes in the side and adding windows and some bench
seats in the back. My bus is described as a 12 seater mini-bus
on the ownership documents.

more interesting banter later,

by Lee.