I would like to suggest adding default options to the Lesson Settings. When a Lesson is created, defaults for navigation for content pages could be specified at a single place. For instance, suppose 90% of your content pages will either direct the student backward to the previous page or forward to the previous page. At the settings page, you would select "Previous Page" and type in "Back" and select "Next Page" and type in "Forward" for the default navigation options.
Then, when creating Lesson Pages, there could be a check box that says "Use defaults" so that if nothing is placed in the navigation boxes, the defaults, "Back" and "Forward" would automatically appear. If the checkbox is unchecked (or when someone types something new in any of the boxes), the defaults are ignored.
This would save a lot of repetitious typing and mistaken directions by allowing you to set this once instead of every time you create a page.