In my case I don't have any seats in back, and access is either climbing between the front seats or climbing in from the rear.
I have a split bench seat from an '89 Chevy pickup that looks like it would fit width wise (snugly), and which folds and slides forward in a way that would open up the rear for seating, at least for the young and limber. I may someday put that seat in, especially if I happened on some rear seating that would make sense with it. It needs to be recovered so I've not done anything yet.
