The system permissions really baffle me.
The 250GB drive divided itself into C and D. C is reserved space for the OS and its functions. I can read and write to D from any network access.
To deal with the other drives, I had to put a network sharing folder onto each drive at its lowest level, and then put all the content into the sharing folder. That at least lets me read from any network access, but no write, no matter what I tell it.