One of the fun things about taking a family walk is all the leaves and such you can find. Take advantage and make a collage when you get home.
You can think of different themes or just do a “stuff we found” collage. Maybe look for seeds, or different kinds of leaves.
This can be a great way to encourage the entire family to pay attention to what’s around them as you walk. Not to mention that younger children in particular love making crafts.