[RKDinOKC]

Using VPN Remote Desktop seems to send and receive files about the same as file sharing, BUT usually send comparatively small files around with copy/paste. They are small enough they fit on the clipboard. I assume file sharing would be faster for large map files, but am not sure.

Just a thought. You should be able to set your router that does NAT to you private network to pass public traffic to a box on a specific interal IP. It is called the host machine. That would mean you would just have one machine on each network you can login and copy files to/from. Just lock down the host traffic to only allow the other users IP address to be able to log in securely.. It would be safe and you would not have to purchase any VPN sogyware. The limitation would be just access to one machine on each network. The big thing about a VPN is that you would have access to all machines on the other network, not just one. It you are just sending files to a raid, don't think that would be necessary.