And yet not to be underestimated. Author DB Johnson has written and illustrated three Thoreau-inspired children's books which NPR's Scott Simon and author Daniel Pinkwater read out loud. A real treat. Bonus points if you can match the books with Thoreau's works.
From these links you can download the podcasts, about 8min each...
Henry Hikes to Fitchburg
Henry Builds a Cabin
Henry Climbs a Mountain