Captive enrichment is an issue that's been brought up for ball pythons, especially when the standard of keeping involves bare tubs lined with newspaper and not much else. If you want to encourage your snake to exercise on it's own- which would be the least stress way to do it for the animal- provide an interesting enclosure with areas available for borrowing or climbing, as well as switching new objects in every occasionally. Another thing you can do is scent the enclosure the day before, or morning of feeding: gets them excited and more likely to begin actively hunting if they know food is near by.
Taking a snake out of its enclosure can offer it exercise, but it's coupled with the stress of handling, and taking it to a public park adds danger to your animal's safety as well as possible negative public interaction. If you want to take a snake some place public to show off, only take it someplace it's been invited to before hand.