This project and especially one of the closing notes[1] reminds me of a more mature DIY project to make a mesh node using a simple solar lamp[2]. I love the creativity on display here and I especially appreciate all the links to the other blogs and sites that helped you along the way.
1: > I was talking with a friend about this idea and the storage limitation and he thought it would be cool to have these devices form a mesh network
2: https://meshtastic.org/docs/community/enclosures/rak/harbor-...
Data transfer is so, so extremely limited over Meshtastic it probably wouldn't be worth it for anything larger than a few dozen kB. There are a lot of documents and books that could fit into such a small size perhaps but no novels.