I am lucky in that the ds who wants to "free range" which in olden days was "ride my bike" or "go outside and play" happens to be tall for is age and has always looked older. And I send them both out together many times. Younger ds gets bored easily so doesn't stay out for very long. Once around the neighborhood and he is back in.

...reading is pleasure, not just something teachers make you do in school.~B. Cleary