Yup, I've been working with file links so that it appears as if there's a local directory but it is actually living somewhere else. On Linux, these are created as:
$ ln -s /path/to/target_folder .
This will create a "virtual" folder target_folder/ in the current directory. One can do something similar on Windows - using a completely different command call. But for simplicity, I use R.utils (I'm the author) for these tasks, which is cross platform:
> R.utils::createLink(target = "/path/to/target_folder")
> dir("target_folder") # will list the files in /path/to/target_folder
Now, on Windows, that dir() may not work (depending on file system format and type of link). The fully cross-platform way is to use:
> path <- R.utils::filePath("target_folder", expandLinks = "any")
> dir(path)
This will even follow good old Windows Shortcuts links.
It's been a while since I've actively used it on Windows, but it was working flawlessly for a good decade now and CRAN checks validate the above on a regular basis on all OSes.