I don't really have an answer for you on this question, but I wanted to let you know that I am going to change the format of this topic from a "Question" to a "Discussion". A "Question" typically has one "correct" answer, and a "Discussion" is designed for a more open-ended discussion and could have a variety of replies to accomplish similar things. I hope this change is okay with you.
I have one solution for you, although I don't have all the info from A to Z to provide to you, and for that I apologize.
My thought was this; take the basic elements of the course that you want to provide to prospective students, and make (or have your admin make) a copy of your course with only the elements that you want to be made "public." From your new basics-only course, go to Settings, scroll down to Visibility and change the default (Course) to "Public."
Now this is as far as my smarts go. I don't know how you would necessarily get those students or any other students to access the course, but hopefully this is where someone else can jump in and help make this happen for you.
Hello Again, firstname.lastname@example.org
This article should help; "How do I include a course in the Public Course Index?"
This concept could also solve the problem of publishing the course for visibility, but again, getting students to look for, or find it, could be a separate challenge, unless they know to search public courses.