With version 1.6 of Client Power Tools you can add additional pages to your client dashboard. That means you can restrict any page on your website to logged-in clients.
You can find the new option in your WordPress dashboard under Clients / Settings.

To find page IDs, open the page in the WordPress editor and look at your browser’s address bar. It should show something like http://yourdomain.com/wp-admin/post.php?post=174&action=edit
Look for the post=174
section of the URL. That number is the page ID.
The result will look something like the screenshot below, where Case Results and Level 1 are additional pages, and the Level 1 page has a number of child pages.

Additional pages will be protected just the same as the rest of the client dashboard. That means visitors will have to be logged-in clients in order to see the page content. Otherwise, they will only see a prompt to log in.
I look forward to seeing how you use this feature! Let me know on Twitter, where I’m @samglover, or leave a review on WordPress.org. And you have a problem and you can’t find an answer in the documentation, try the support forum.