Immediately south of Mundaring is Beelu National Park, part of a continuous swath of forest that includes Kalamunda National Park. The Perth Hills National Parks Centre hosts Nearer to Nature kids programs with a flora and fauna spin. There's a good campground (adult/child $7.50/2.20), well positioned for the Bibbulmun Track, which passes nearby.
From November to April, kick back in a deck chair at the open-air Kookaburra Cinema , just across the road from the park centre.