I found my answer in chapter eight in the ORCA/C 2.2 Manual.

My boot drive is: /GSHD1

I store programming files in /GSHD1/MYPROGFILES
C files are in /GSHD1/MYPROGFILES/MYORCA.C

If I set prefix 20 to that path with the following command from the ORCA command shell...

'PREFIX 20 :GSHD1:MYPROGFILES:MYORCA.C'

Then if I type 'CAT 20', the contents of the above path are displayed

To edit a file, then I type 'EDIT filename.cc'

That's the answer for which I was searching-how to set a numeric prefix for a path and how to
catalog or edit files in said path by using a numeric prefix instead of needing to type a
long pathname.