I am using Syncthing across a few computers and have setup an offsite node in another physical location (my parent’s house…), it’s a raspberry pi with an encrypted LUKS volume (external USB drive) that hosts my data. The machine boots up from SD, dials home to my network using OpenVPN (client-side certificate, which I can revoke if compromised), then emails me asking me to unlock the encrypted volume (which is done using a simple node.js app), mounts the data volume, and reloads syncthing which will begin syncing from that point on.
If this device gets stolen it’ll be disconnected from power and my data remains safe. I still run a risk of a local network exploit while the machine is online, but that risk is low and I’ve got no open ports (except over the VPN interface) and I run automatic updates daily.
I’d obviously much prefer a syncthing node which doesn’t ever see data in the clear, that would enable proper cloud hosted safe storage, but just wanted to propose this approach to people who are seeking a temporary solution.