NAS that allows cloud access and backup to remote duov1

All that should be required is getting to the "Port Forwarding" area in your router's admin interface and forward the required port, to the required IP address on the local network at the remote location. The cable router that the Duo sits behind will block any incoming unsolicited connections, as with any router. Outgoing connections from the Duo won't be blocked. Nor will return connections initiated by an initial outgoing connection on the same port (from the duo end).

But even setting up a VPN would require router configuration, and would take more time to set up than simple port forwarding. The only question is then do you have ownership of all the kit at the remote location to perform the required change?