Here is what I did on the two 85 Vanagon conversions I did (86-91 vacuum hose
setups are slightly different but the same principals apply).  I got a 90
degree and "T" fitting from Home Depot.  I installed the 90 into one of the
normally plugged holes in the large intake air boot (there are two plugged
holes, take your pick).  Then I ran 1/2" hose around the engine compartment
just under the lip where the engine lid rests.  This allows you to put in a
long run of hose without anyone seeing it or it looking ugly.  I ran the hose
over to where the clear plastic line is coming through the firewall and would
normally hook up to the airbox on the 1.9l.  I installed the "T" here between
the clear hose and the hose from the intake air boot.  The bottom of the "T"
will point toward the pcv valve.  Turn the pcv valve upside down and install
a very short piece of hose between the bottom of this valve and the "T".  Now
run your small diameter vacuum line (3mm) from the small fitting on the pcv
valve to another smaller "T" (you should be able to salvage one of these from
your old vacuum line setup).  Install another small piece of hose from this
"T" to the fuel pressure regulator, and the other end to the intake manifold.
 This should do it.  That way you don't have alot of unsightly hoses running
around your engine bay making things look crappy, you don't have to splice
into your brake vacuum (which is what Peter did), and everything should work
fine.  The one kit that I got emissions test info from NY State, tested way
below all emissions standards for the 85 Vanagon (almost 10% of what was
allowed in a few catagories).  Hope this helps.

Thanks,
Ken Wilford
John 3:16
www.vanagain.com
Phone: (856)-765-1583
Fax: (856)-327-2242