I am also looking at having to re-attach carpet to the floor of my
Vanagon.  I am intending probably to replace my carpet soon, but in the
interim was thinking maybe velcro might work.  I don't really want to
attach the carpet with glue since it may bond permanently with the pad
underneath and be more of a pain whenever I get around to replacing the
carpet again.

Just a thought.
-Dean.  84 Vanagon.