Hi Ana,
Hope everything is going well.
Three years ago, I started an initiative in Puerto Rico called The Keep Growing Project and it looks like a Forest School concept. Students from different parts of Puerto Rico came to the San Patricio Forest to take a workshop with their parents in Earth Day. It is something beautiful to see, they are completely engaged and motivated. As you mentioned creativity and collaboration are part of this approach and came so natural as the environment they are immerse.
Try it, it will be an amazing memory for your students and for you. If you find a tree house better- Best of luck.