Thanks for your responses, everyone. Here's what I found:
Potential Solution 1: Add the system attribute via the Command
Prompt (attrib +s +h /s /d c:\Windows). It works only if the
user's Windows Explorer folder options is configured to Not hide
protected operating system files. So I cannot use that solution.
Potential Solution 2: NTFS permissions: They work great in
keeping users from browsing a folder's contents but, as in
solution 1, they won't hide the folder if a user's Explorer
options allow them to see hidden folders.
I even tried creating a hidden share. No good, for the same
reason above.
So, I don't have a solution yet, but I'm open to other
suggestions.