Hi Darrell,
If you use EQMOD, you can control your EQ5 and guide all through the EQDIR. Meaning you don't need to use the GPUSB. The EQDIR will do the work of the HC and guide port all in one. Meaning less cables. All you will need is EQMOD running and a planetarium software such as Cartes Du Ciel.
What you will then have is.
DMK to laptop
Serial (RJ45) cable to EQDIR
EQDIR to Mount
Run PHD
I suggest you run EQMOD but the process you have described will also work.
Hope this helps.