Hey @mmwilliams!

This is a fairly simple process.  Once you are in the course, click on Settings  in the course navigation menu on the left side of your screen.  When the Settings window loads, locate and click on Reset Course Content on the right side of the screen.  Follow the prompts and all of the content should be removed without affecting any of the student enrollments.  

In my experience, if the course is already published this this process will unpublish the course.  So, make sure to publish the course again if necessary.

Good luck!