Agree, she probably wouldn't be that hard to find, and at this point, I'd say it looks like your best bet. Odd that if you take that approach (she would want to know) that the present "care takers" won't give you her name... Anyway, you or the niece (assuming she does care) could probably arrange to perhaps have someone from the local herp society or a local rep. savy person to get the snake and mail it FedEx (not sure how that works from the Sender's end), or perhaps they can find someone local can give it a good home.
Sorry to read about you going through all this.
I hope it gets a good closure.