If I've read the post correctly, you want to use the USB connectivity of the 18F4550 in the same way as using the normal serial statements when communicating with an RS232 type port. USB connectivity isn't that straight forward, however I would suggest that you look at using an FTDI based USB to serial converter, either as one of their cables or a small breakout board. This will mean you don't need to change PICs, and have USB connectivity at the PC, with the connection being seen as a standard COM port on the PC. If you get a genuine FTDI chipset (ie not a doggy £3 cable off e-bay) the drivers are supported under windows 10.