I came across this simple writing sheet that I created two years ago when I did make-your-ending stories with my sixth graders. We actually used it twice: first, as a collaborative writing prompt, where one student began a story and then passed it along to someone else, who then branched it out and passed it, etc. Second, it became a graphic organizer for their own stories, which we later published on our wiki site. It’s nothing fancy, but it is a good starting point for this kind of branching story.
You can download the organizer or view it here.
I also found this concept/site map that I had created for other teachers to explain how to teach Make Your Own Ending stories. The map is part of a website that I had created called Threaded Adventures. It’s still a valuable resource, for me.
Peace (along the branch),
Kevin