[fontgeek]

How about an old apothecary/druggist shop that specializes in poisons. Save your bottles, prescription containers, etc., and create new labels to reflect the potential poisons.
You. can fill the containers with anything from rice, syrup, gummy drops, to plain water or juices.
I think a big part of the challenge is not the info. for the areas, but you getting enough actors to occupy the various "shops" or zones for the party.

 

[fontgeek]

I'd hit some thrift shops, flea markets, etc. and look for inexpensive items to fill your "shops", maybe knives and bladed instruments, and make up posters or POS ads listing all the features pertinent to particular knives for murder, direction, etc.
Again, my worry or concern would be having enough actors to cover some of your "shops".
Things like the apothecary aren't a big deal, but if you do something like the blade shop, then I think you need to have someone there with it. People get stupid, especially if they drink, or just think that these are all fake props that couldn't hurt them.