I imagine it would be possible to set up like a kiwix server with text and PDF files of these books downloaded from Gutenberg, using only of course public domain copies, and then set up a QR code that would allow someone passing by to pair with your kiwix server, download those books and then have their own copy of them.
Books are small files which aren’t big enough for torrents to be useful. Go ahead and look on z-lib, which has whatever book you could possibly want available for direct download