Nick,
As the owner of a 1985 Westy Wolfsburg "weekender" (terminology seems to
vary with this vehicle-mine has poptop, closet, folding bed, jumpseat,
removable refrigerator) with a 2002 2.5L Subaru conversion, I have a few
comments:
1) This is a very flexible, and somewhat lighter, package.  I love not
having all the interior loss of room, as I depend on my Westy for hauling
kids to school, Home Depot runs, mountain biking and camping with my wife
abd 2 kids.  I like to cook and clean outdoors anyway.
2) with a Subaru 2.5 and factory A/C this van really scoots up the
mountains here in Colorado-I can summit 11,000 feet fully loaded with
camping gear and passengers at 65+ mph in 3rd gear.
3) Do not buy an aftermarket cruise control unit if you are planning a
Subaru conversion; the Subaruvanagon web site on Yahoo details how to graft
the factory Subaru cruise control unit (if your donor came with it) to the
VW controls.  My aftermarket (older style) cruise control unit will not
operate with the late Subaru ECU in my car.
4) The only advantage to the '86+ "Weekender" camper is newer.  Once you
pull out the VW engine and electronics/FI it really does not seem to
matter.  Only thing the '86 will get you is a tach in place of the factory
clock, IMHO.
5) On the '85s you can upgrade headlights easily to 7" round H4 units for
much better on and off road lighting.

Connor
85 Westy weekender/02 2.5L Subaru RS