The easiest way to do this is simply select the 'Hidden' attribute in the folder's General properties tab. Of course, you also want to make sure they don't have the 'Show hidden files and folder' option enabled. You can also use the Group Policy Editor to enable the 'Remove folder options from Tools Menu' so they can't enable the viewing of hidden folders. They will still be able to access the folder from the command prompt, however.
I doubt you can enable access to the files and disable displaying the folder contents with special permissions, because the 'List Folder' and 'Read Data' permissions are linked together in the same permission.