I can relate to you what a local "VW" specializing garage told me.  They were
quite adam ant about buses needing new head gaskets before 90,000 miles.  They
said that probably every vanagon in Gainesville had the gaskets replaced.  My
scenario was that they were doing a pre-check on a vanagon I ended up buying.
It had some residue and they thought it might be leaking.  WEll, it sure was.
Tons.  
I made it back to St. Augustine and have parked teh thing until this weekend
when it gets the heads pulled, shaved, etc. etc.  I also had the little light
coming on, althought by the time I got it, it was using major coolant.  I
filled it up with water to make it home and am hoping I didn't do unrepairable
damage to the heads?
I've also had a person from around here tell me that they had VW pay for part 
of their repairs, who knows?
chuck