You may want to check out
C.A.R. in Holyoke. I don't think that's too far from you. They carry a few product lines, but I've never been there personally. Also,
5959 Auto Designs is the local Poorboy's distributor. He may be able to sell to you direct or point you to a store that carries PBs products. As far as Optimum, I would contact them directly to see if they could give you info as to who is their local distributor.
Honestly though, IMO it's less hassle and often less money to order products on-line. It is nice to find a place where you can quickly pick something up if you're in a rush though. Unfortunately, with our long winters in New England these are not really profitable businesses. So, few exist here.