I used b-quiet (blue, not alumnimum) on my engine deck, under the rear bench, under the front seats and in the front doors.  I still have some of the stuff I planned to do other parts with...  lazy... or busy...  It does quiet things down some, namely road noise and engine noise, but it doesn't do much for wind noise... for that you really need to replace the weather striping, which I did and is a PITA IMHO.

One thing about b-quiet...  on my doors it's had slid down, ie. it got so hot that it melted off and end up a the bottom of the door...  yuck...  messy...  I attribute this to two things 1) I live in SoCal and there are times when I park in the sun that the doors probably get to 130+ degrees from being baked in the sun, 2) I did not do a through job of cleaning the surface it was adhearing too.

My suggestion would be two fold, 1) use the roof sealing tape stuff, it's probably as good if not better; 2) clean the surface throughly, chemically and some scrubbing no matter how hard it is to get in there andscrub.

Note, the web-site linked in the previous post shows putting the stuff on the outside of the door, my research indicated it was to be put inside the door...  

Here are a couple links just as FYI's:
http://www.b-quiet.com/vanagon2.html

http://www.soundprooffoam.com/

http://fullmoonbusclub.com/modules.php?name=Forums&file=viewtopic&p=9321