You can extend Gatekeeper protection to more pages by using Stack-Keeper.
Documentation
Stack-Keeper provides two drop-zones: On for content which is displayed when Logged In and one for content which is displayed when not logged in.
Gatekeeper ID - this is the counterpart to the setting with the same name in the Gatekeeper stack. The text entered here connects both stacks and enables Stack-Keeper to determine which content to display.