...if you are worried, then by all means, invest in some pepper spray and basic self-defense knowledge.
But on the other hand, I’ve lived in some pretty rough neighborhoods in my life, and I think the key thing is just to be alert to one’s surroundings… not just things that send up “alarm” bells, but things that send up “safety” bells—knowing where there is quick access to an open shop (a little more difficult on a trail than walking through the city, granted), other “good” people out on the same walk… there was a study done that said people were more likely to respond in an emergency if they were called on specifically, even if it’s just “hey you! guy with a red hat” so I would always try to have a couple of those people marked out in my head in advance in case I needed to shout to them.
And it’s important to, to remember that things aren’t people—smashing a car window is not at all the same sort of crime as assaulting someone. First off, it’s anoymous. It takes a lot less guts on the perpetrator’s part. Secondly, if it was part of a theft, a car can’t “comply”... it’s not like in a person-to-person situation where you can get mugged and have your wallet taken, but walk away physically unharmed. (Not that I’m trying to negate or judge crimes here… the risks are far greater if something happens to you, definitely, but my point is that the odds of something happening are lower than vandalism against an unattended car.)
Meanwhile, and a bit off topic, Doctors are finding that many people in the northern hemisphere are vitamin D deprived… if you know you’re not getting enough sunlight anyway, and you’re feeling draggy, you might want to have that checked/start taking a supliment. (I am not a doctor. This is not professional advice)