One more thing, I am not trying to tell anyone to configure their van
one way or another, just that there are little things that can be done to
improve mileage.  The biggest is keep the speed down.  Any Westy going 80 is
going to get 17 or less mpg.  Carrying stuff on the roof will also cost you
a lot, but that might be your sole reason for owning a vanagon so you
obviously aren't going to take them off.
    A modern engine conversion (Subi, Zetec, VW I-4,whatever) should give
you 2-4 mpg better, driven at the same speeds as the WBXer.  Taller gearing
will help 1-2 mpg if your engine can handle it.
    3 bucks a gallon blows.  I used to care about the mileage of my Westy
because it decreased range when you are in the middle of nowhere.  Now it is
just getting expensive to drive anywhere. 24-26 mpg vs 17-19 with the WBXer
helps a lot.

    John