Well, I made it out there! East Coast Zoological had a few animals and a really cool albino corn snake, but only one caudate, a fire salamander. Not a lot of stock, though. On my way into Newport, however, I found two other pet stores, not chains, and much bigger inside than they appear. Both had LOTS of fish. In the second one I found a folding top for my new 48" tank; I didn't even think they made them that big!
I did notice that caimans seem to be very popular in Rhode Island. I made such good time, I revisited the Roger Williams Park Zoo, which is having a lot of work done. One of the buildings with herps was closed. I saw some cool snakes, though. The rest of the visit had nothing to do with animals, so I'll spare you all the details.