Old Granddad belatedly weighs (too much) in on the subject:
A lot of kids these days may be kept in by their parents simply because it's nowhere near as safe a world as it was say, forty or fifty years ago. We used to go across the street to a big park and play all day, only coming home for lunch and dinner. Not a worry in the world about perverts or gangs or drugs or such like. No more. It's a much scarier world out there in which to raise kids.
One way to give kids increased exposure to outdoor activities is to get them involved in Scouting or similar organizations. Recent scandals notwithstanding (where
were those kids' parents, anyway?), they're top notch outfits for kids. My son's troop went camping once every month, no matter what the weather (well,
I was a lot younger, then, too). My sister is still very active in district activities for the GSA at the age of 67. My other sister never fails to break into some of those inane summer camp songs (ahhh, Camp Wind Mountain) when she wants to get on my nerves.

You know the drill. Of course,
I have no tricks for getting on her nerves. Nope. Not me. Uh uh.