Hi @Grubstake,
Not much else...
You can have node running (as a service or daemon) on any device that has a USB port (PC, mac, RPI) and it is agnostic of what controller you have.
Are you interested in the code details? Check the MySensors post I included in the link.
The MySensors typical messages is something like this 30;5;1;0;37;70
Which gets translated to /whateverpathyouwant/out/30/5/1/0/37 Payload: 70
And vice versa.
The reason I did this was because I had no WiFi or Network enabled gateway.
Cheers