Realistically, there is no way to connect a USB device to the cFP-2020.
I don't know the specifics of USB protocols, but I don't think it is possible to convert a Serial signal to a USB signal. I know it is possible the other way around, but it does not appear to be a 2-way street.
Even if you could get the communication to work, it would probably be difficult to convert all of your calls into VISA commands so that the commands could be sent along the lines, and then you would have to develop a way to parse the returned data.
Technically, it might be possible, but you would most likely be headed into territory that nobody else has gone into before.
If you still need to connect the USB peripheral device, then you might want to consider setting up a system that can do USB communication in the vicinity of the cFP system. Another option would be to get a
PXI System, that way you could have all the advantages of an RT system and a PC.