RE: Best Year
As with most of the other answers you will get my experience is anecdotal,
based only on my experience.  I've put about the same time/miles on two
Westfalias, an '85 and a '90.  The '90 has been, for me, a great improvement
over the '85.  A little more power, much more relaiable, and a much better
driving vehicle.  I'll qualify my answer by adding that if I had known as
much about the Vanagon when owning the '85 as I do now with the '90 I might
have had the '85 driving as nice as the '90.  But the engine, brake, and
suspension changes in '86 and on were improvements.  If I had to replace the
'90 I'd only look for an '87 on.