Then I remembered that I had done something on a smaller scale with first graders a few years back. My very first long-term sub job was in first grade and went all the way through the end of the year. So I had the pleasure of coming up with educational, creative ways to spend some of the last days of school. I created an End-of-the-Year Advice Book for my students to leave for next year's students. The students got very excited playing the role of expert and telling the littler ones how it should be done.
So I updated that rudimentary file I made years ago and am offering it to you as a freebie. All you need to do is make copies of the book for each student, fill in the current grade level, and let students complete the book with words and pictures. The book is intended for lower elementary grades, but I am sure even some third and fourth graders could get a kick over giving advice on how to survive their grade.
As far as distributing the advice to next year's students, it's really up to you. You could give the books to a class of students, spread them out through all the classes, save them for your own class next year, or send students to each class to present their books.
Anyway you do it, I guarantee that the students will have fun, and you will learn a lot from their perspective. It might even open your eyes a little, leading to some reflections about what to change for next year.