Sorry, I don’t have any lesson plans to share, but I can tell you that in one of my high school lit classes, we studied the Hero’s Journey without ever learning about Campbell. The teacher there just taught it as a model by itself, using a circle as an illustrative tool.
On a side-note, I know you will probably see it, but I just created this topic: https://www.jcf.org/resources/discuss/topic/suitable-for-young-people/