re:  The lowest cost out of pocket is to do it right yourself

Doktor Tim's writeup on this is really good, and I think folks should
take the sentence above to heart.  It might be good to compare oil
changes to pumping gasoline.  There are fewer and fewer places where
an attendant will come out and pump your gas, wash your windshield,
and check your oil.  (I don't actually know specifically where to find
one.)  You do it yourself.  Think of oil changes like this.  The only
difference is there are places that claim they can do it, but they
absolutely cannot do your Vanagon, and if I owned a Chevy I'm not sure
I'd trust them to do that car correctly either.

Think of these statistics.  (someone can provide correct numbers).  In
the USA, xxx Vanagons were sold between 1980 and 1992.  During any
given year during this period, Chevy probably made more of any given
model in a month than VW sold Vanagons in the USA during the entire
10+-year period.  Chances are about 99 to 1 the "mechanics" at the
quickie lube places have never seen a Vanagon before.

 And, pretty much every engine Chevy put in those vehicles was either
a 1955 or early 1960s design, hardly changed since.  When your Vanagon
was new, even the best Chevy mechanics at the Chevy dealer  never saw
a vehicle as sophisticated as the Vanagon--they still haven't.  The
fact that your Vanagon may be 20 years old and is only worth $2000
changes nothing, and chances are about 99 of every 100 mechanics you
find have never worked on a Vanagon and most of the 99 probably don't
want to and most don't have the book and most won't be able to figure
it out by looking.  Chevies just don't have "plugs" right next to the
drain plug that are really the oil pump, etc.