Limit the settings within your database
Go into the database Options (Office Button->Access Options->Current Database) and uncheck elements such as:
Display Navigation Pane
Optionally:
Allow Full Menus
Allow Default Shortcut Menus
While you are there ensure that Track name AutoCorrect Info is not checked. As well, you should not ever use Compact on Close.
Control the type of file your distribute
Be sure to convert (Database Tools->Make ACCDE) your front-end into an *.accde file for distribution to your users.
Remember that error handling within your procedures becomes very important in mde/accde since users cannot debug the code.
Remember though that you need to always keep the accdb, since that is the format that allows you to continue development.
Make your own Ribbon
If you were to create your own Ribbon(s) and disabled all the built-in ones and hide the nav pane, you could basically completely limit what the user sees, and has access to. Thus they would only be able to open whatever you’ve created buttons, and other controls, to open.
Security
Either create a login form, or a table that you cross-reference the active network usernames against to stop nosy employees from getting into the database in the first place.
I also urge you to take a look at Allen Browne excellent post: http://allenbrowne.com/ser-69.html
Folder Permissions
Set the Back-End folder permission to ‘Traverse permissions’: “it allows users access to a folder on a network share without them being able to see the folder without knowing its full address. Essentially they have access to a dummy folder on the share, but they can’t access the storage folder unless they know the exact address.” – Scott Gem
Also setup the permissions on the folder so that only your specific users can access it. This will stop users who have no business in your database from ever being able to see it, let alone mess around with it.