Require logged in user for all pages except for:

• The Home page (of course)
• Registeration page
• Forgotten Password Page
• The "externalpages" plugin pages (Terms, Privacy, About)

For developers: If you would like to add more allowed public view pages, you can register your own hook:

register_plugin_hook('login_required','login_required', 'your_function_name');

Make sure to return an array of page URL's. For more information, I have a working example in the plugin itself made for demonstration purposes.

To allow access to profile pages: Change the following:

if (!in_array(strtolower(trim($current_url)), array_map('strtolower', $allow)))

  gatekeeper();

to 

if (!in_array(strtolower(trim($current_url)), array_map('strtolower', $allow)) && get_context() !== 'profile' && get_context() !== 'widget')

  gatekeeper();

Note: If you do not want the widgets to show any content, you can remove the 

&& get_context() !== 'widget'

from the end of this statement. It will allow access to the profile page showing the profile information only.