Hi Andrew, welcome to CocoonTech!
The demo has some restrictions, but you should be able to see some devices. Did you use the Sync function? Also, in RP, did you set the "Show" flag for the lights/outputs?
If you want to use ElkRP over IP, without having the ethernet interface, you will indeed have to create that virtual serial port (hw_vsp). I tested it, and it works great, just keep in mind that when connected with RP, using IP, all other communications will be suspended until RP has been disconnected.