Speaking of rural mailing addresses, I was just reading an article with an update to an old story about a woman who lives alone in the Russian taiga, far far away from other people. She and her family lived isolated there from 1936 to 1978, when they were discovered by scientists. Since then and since the deaths of the other family members, some scientists have kept contact with the woman and bring her food and other items from time to time.
In the comments on this article, somebody said he wished they'd post a mailing address, as he'd like to post a package to her of some nice foods/supplies to help her out.
(In an isolated, hard-to-reach handbuilt cabin so far from civilization that it went undiscovered for 40 years and still is only reached by explorer scientists with special equipment. A mailing address.)
On the face of it, it sounds like a silly comment - but you could make an argument that the Scientist could have given a mailing address so that any cards/parcels/whatever could be taken up the next time he visits