Library updates without Internet?

Hi all,

I’ve searched and have not been able to find any ideas on how to solve my particular problem. I have a friend who I’ve built a Pi3 box for with an external HDD storing media. They live in the country with no available internet options (outside of satellite, yuck) and are older and not very tech savvy. The setup has worked beautifully for them, however updates are a pain as I have to physically return to the Pi and HDD back to my place to add media and then update the library.

Here’s my question: What would be the best way for me to bring a flash drive to their house with new media as well as the database/metadata/artwork and be able to apply those updates to the existing system? I’m comfortable writing and using simple shell scripts, and I hope I’m able to do what I want using this. Can anyone lend me some direction to figure out a graceful way of updating their setup without dragging it back to a WAN?

Thanks in advance,
Eric