Hi Phil,
I borrowed a customized Reese tow bar to tow the Westfalia I bought last
summer. It's bolted to the front bumper (chrome cover removed first) and
extra metal brackets are attached to the left and right lower control arm
bushing plates. A total of six bolts, and I towed a Westy with my Westy 500
miles.

Word of caution-no matter what you tow with, your top speed is 50 mph. Also
you may need a new clutch from the extra load (still cheaper to replace the
clutch than a shipping co charge of $1,000).
I think I took pictures of the set up. The front bumper cover is held on by 4
bolts. The Reese tow bar is adapted with steel bars to reach these points,
and the two underneath.
The tow bar is about $100.00. I also think it is a better way to tow,
because your van will handle better-there is no weight on the tongue. the
heavy load of the tow dolly with a heavy Vanagon on it will cause the front
of the Vanagon to "float." When I find the roll that has pictures, I will
make them available.
Robert