A few people have asked about adding an interior rear hatch release.
Apparently only some 1990 - 1991 vanagons came with this feature.  My 87 did
not, and I think it's very worthwhile. On hot nights you can easily open the
rear door to get some ventilation.  It only takes a half hour or so to do
it, nothing to complicated.
I can't really explain in words exactly how to do it, but if you remove the
rear door panel and take a look at the mechanism and how it works you will
see what needs to be done.
In a nutshell, I used a thin piece of 1/16" 7x7 wire rope attached to a hole
I drilled in part of the latch.  I swaged one end of the wire rope to a
little hole I drilled in the latch,  sailboat rigging stuff.  The wire rope
passes through a hole in the rear door panel.  Pulling on the rope releases
the latch mechanism.  You could probably use a thin piece of strong rope or
line also.  I used wire rope because I had it available.

Picture here
http://www.telusplanet.net/public/gary2a/rack/westy/westymods.htm

Gary Lee
http://www.telusplanet.net/public/gary2a/rack/vanagonrack.htm