Really cool thread.
If you are a Blade forums member the Traditional knives subforum frequently has a thread of this nature. That is why I like visiting that subforum.

For me it was a mix of running around in the woods on both a rural and urban scale. I grew up on Long Island back when it was still mostly farms. But in a span of 10 years a lot of subdivision went on.
We would use the random patches of woods and streams as our personal highways to our friends houses and to and from school.

We used these woods for campouts and fort building as well as our own precurser to mountain biking.

One unique thing about our neighborhood was something we called "sumps" these were storm drainage basins that were scattered throughout the neighborhoods to recharge the natural aquifer. These sumps were our personal fishing grounds; they usually had a combination of carp, bluegill/sunfish and LM bass.
Other sumps were mostly empty and we went "spelunking" in the large pipes that ran from the street drains to various sumps. Many sumps were linked together by the pipes.

On LI we had both fresh and salt water fishing, lots of creeks and scattered woods.

Usually we stole an old cookpot from the kitchen along with some strike anywhere matches, our fishing gear and our pocket knives. Mine was usually an SAK. We were not allowed real guns in my house but I usually shot my friends Crossmans and .22LR bolt actions on occaision.

Funny thing is I do not remember carrying a flashlight ever but we were usually supposed to be home when the street lights came on. In summer that could be as late as 10PM!! We had tons of unsupervised fun in those days.

I will bet that a lot of our mutual experiences in the woods as kids helped build a good foundation of skills.