Yes. Set up the config to point to a new directory in \Users<your name>\AppData\Local\Topten Software\Cantabile 3.0(x64) (newname)*
Best way to do that is to copy your existing config. The (newname) with parenthesis is the new config directory. After you have that sorted and your directory is working, start C3, go to Tools-> Options -> File Locations. That’s where you set different directories for Racks, Songs, etc. Check the C3 instructions, but after that you create a Windows Shortcut and point it to the new AppData config directory–the one with the parenthesis.
Set your file locations where ever you want and that information will be saved in JSON config files in the AppData directory. Shouldn’t be a need to muck around inside the AppData directory.
*Your directory may be slightly different if your running 32-bit or have other systems settings different.
(Now @Neil_Durant can follow along with a much better explanation, screen shots, a video, and whatever corrections are required )