I just have to put in my two cents. I am a survivor of a violent crime. It happened 16 years ago, when I was recently out of high school. I am now more aware of my surroundings, and I have learned to trust my gut. It sounds like leftover has gotten the good advice, and avoided the bad. I'm very glad for that.
As for myself, I don't feel comfortable caching alone, but I have the good fortune to have a husband who enjoys caching as much as I do, so I don't have to go alone. He's also a big guy...former Marine...if we were to walk into a situation that got ugly, he is very well trained and would give a bad guy a run for his money.
For other women looking for tips, I think the best ones are:
be aware of your surroundings, if it doesn't feel right, don't go there
project a confident attitude, predators (the human kind) are looking for easy targets mostly, if you don't look like a victim, you probably won't be one.
if you plan on taking a self-defense course, it will only be useful if you practice it regularly...otherwise it won't come to you as an instinct when you need it
Have fun caching, just don't set yourself up to be a victim.