Last night I had to tow a van for a mile, from where it was standing for a year.  A friends van.  
Halfway one wheel fell off, sparks all over.  Shaking my head.  The wheel ran off the road into someones yard.
Lol.  Had to take off a nut from the other three wheels I had nuts on.  That reminded me of the joke;
The guy is changing his flat front of a mad house.  His lug nuts fall though the grill of the drainage system.  Now he does not know what to do.  One of the guys that hang out of the windows of the building shouts advice, to take off one from each of the other three wheels to have at least three on the one he is changing, to be able to carry on.  He says; how do you know this?  Aren't you supposed to be mad?  The guy answered back; yes, we are all mad, but not stupid.
Well, the thing is, it would not work quite the same on the Vanagon.  Bolts in the front, nuts in the back.  But you can still take some off and roll carefully.  There are five on a wheel.  Even two is holding a bit.  Not recommended though.  
Zoltan