Sounds like a good excuse to service your fridge if you have not
pulled it for a few years.  One the fridge is out you can see pretty
much everywhere a critter would go.

A 13/16 open end wrench is best for undoing the propane line at the
fridge, but you can use a crescent wrench or Vice grip if you have to.

Ben has some helpful photos/notes here:
http://www.benplace.com/fridge.htm

>For the last few days, I've smelled an awful smell, like a dead
>animal, in my Westfalia. I've sniffed around, and think I've
>narrowed it down to behind the fridge or behind the whole cabinet
>system, in the wall behind the camper inlets. I can smell it from
>the fridge vent and when I pull up the "dummy floor" of the cabinet
>next to the water tank. I've never pulled out the kitchen unit or
>the other cabinets, and I really don't want to. Any suggestions for
>a place to start to look? Maybe take out the fridge and look there
>first? I was even thinking of pullin out the water and electrical
>inlets and fishing around with one of those "grabbers" that are
>about three feet long with a button on the end and the three hooks
>that come together on the other.
>
>What's the best way to find a dead animal with minimal tearing apart
>of the van?
>
>Thanks,
>Ed in CT