Their URL is NEHERP - Your One Stop Vivarium Shop!.NEHERP near Hartford.
I have rice flour beetles, tropical springtails and temperate springtails and dubia roaches(all sizes) if your interested...
I haven't seen too much as far as stores carrying dart-related supplies and animals in Rhode Island, but there are definitely a number of individuals with animals (and I'm sure feeders if you need them) in the area.
-Pat