About adding drive letters that correspond to macOS folders. At the initial C\> prompt enter
echo mount e: ~/Path/To/TheFolder >> autoexec.bat
Note the double greater-than sign. Use that command as a model for similar ones; or simply edit the autoexec.bat file that was created by that command.
About changing drive C (and other drives): in the existing system: that could be done by creating a custom version of the application, but it would take some time. I’m willing to do that, but I would have to charge a fee for a private consultation, because the result wouldn’t be usable on anyone else’s system.
Alternatively, if you want to experiment with doing it yourself, you can work on the AppleScript and other files. Everything in the system is editable by anyone.