Dusty:
I had a very good experience with Fat Mat sound deadening sheet goods.  Purchased 100 square feet for around $95.  That was more than enough to do the entire area over my engine, over the area behind and under the rear bench seat, both front doors (against the inside of the external skin), the sliding door, the front seat podiums, and the area around the front heater.  I have a lot left over.

It has made a huge difference in internal noise.  The front doors shut nicely with the little bit of extra weight and sound very solid. I cannot hear my engine from w/in the cabin of the van and there are no more rattles coming from the doors.  I couldn't be happier with the product.

Warning:  If lining your internal doors, cut the product into 12X12 manageable squares.  It is very difficult to work with anything bigger than that unless you're working on an easily accessible, flat surface.   And.. the inside of the 91 Multivan door was coated with a wax like substance (probably to prevent corrosion).  Make sure you clean that off so that the sheet good adheres properly.  They provide a cleanser product and instructions with the fat mat which I was able to purchase through eBay.

Thanks,
Brent

Brent

> needless to say, i don't know what to do.  does anybody have any
> experience with installing any sort of sound-deadening material?
>