I have sent a USB drive to Ireland, by mail. It took 160 hours, end to end, for 250GB.
Meaning: the sneakernet transfer went with 434KByte/s.
It would have been much faster if we did the transfer over the internet. My connection is 1Gbit FttH. The other end would be the limiting factor, since they have a 80Mbit connection.
If we calculate in some overhead and transfer those 250GB at 70Mbit/s, then it would have taken 7 hours and 56 minutes.
Cool excersize though!