I have a dead raccoon trapped under my deck. Problem is that it is in a
location I can't reach unless I tear the deck apart. I have no problem
letting it decompose naturally but the stench is bad and I am worried
about


How did the racoon get in, then? There's obviously a racoon-sized hole
somewhere. Stick a wire-noose through that hole, and poke/drag it
over to the corpse with a stick and/or hooks down through the cracks.

Failing that, grab a shovel and dig a tunnel.