On natural features...
I moved recently and as a result the closest stop to me is on a highway access road. Prior to moving I'd often let my son go to the nearby park to visit the gym and 4 regular stops. I won't let him him go to the one and only stop nearby because traffic on the road it's on is in excess of 50Mph.
I nominated some neighborhood features for stops/gyms and one of them in a pond. I was chatting with other local players and they said it may not get accepted as it's a natural feature. A few miles away is another pond that is a stop.
I also nominated a pool, a basketball court and a playground. All are types of stops I've seen around town.