A 'Woonerf' is also a Dutch invention and used whenever possible to build new houses. That helps a lot to give younger kids safe autonomy, traffic is sparse and slow in a woonerf. My childhood shares a lot of similarities with yours, pedaling around the nearby neighborhoods looking for fun. It seems that would be a lot harder in a (more) car centric country

I love hiking nowadays but the avondvierdaagse felt like a mandatory thing when I was young. Maybe missing out on it was an even bigger motivator than participation itself back then.