Hotch,
You can chemically strip the paint off the van, however, there is no way
you can "just" take off the poor quality paint, without screwing up the
the factory paint,or whatever good paint is under it.
There is just no way to control, how much you are taking off at any
given time.
The only way that I know, to remove the unwanted paint, in some sort of
controlled way, is Sand the garbage off, prime it, and repaint.
Sorry about the bad news, but there is no better way, to do it right.
Terry
85 GL