I have the info I need to get rid of my path separator variable and probably to stop editing the #! line every time I copy the code to Windows.
I can move my module to one of the standard directories from @INC.
I still have to edit my config. file when I move the code, though. That's actually not too much of a burden, but I think I may have found my solution in the %ENV variable SERVER_SOFTWARE: on the Linux server it shows Apache/2.0.55 (Unix) ... and on the Windows server it shows Apache/2.0.55 (Win32) ... ... That'll work :D