In the last 5 years actually more like 8 years now that I think about it.
Colombia, Costa Rica (3), Belize (6), Panama, Scotland, England (2), Belgium, Holland, Hungary, Austria, Czech, Vietnam (2), Laos, Cambodia, Thailand, Japan. And planning Chile/Argentina now and Pakistan is also on my short list.
At least 75% of those are solo. The thing I hear most from people is that they just assume every place is dangerous. Not once in any of those countries did I feel in danger in any way what so ever. I also don't do stupid shit. I assume most Americans would say sitting outside a soccer stadium after a game in Medellin drinking .50 beers with the locals is dangerous. It is not.
A little advice. Do a little research. There is so much content available. Stay out of places you shouldn't go. Find several solo female vlogs or blogs. Solo women no doubt have to be more careful than 52 year old dad, esp in countries where woman have less rights; so listen to them. Leave anything valuable or flashy at home even if its not expensive.
Group tours are great for those not wanting to set out on your own. A group and a guide is safe. I also like them because they are cheaper and efficient and you get to meet lots of people. The draw back is that you are stuck on a bus/van with people. Viator is my go to for tours.
I've never met so many amazingly nice people traveling. It's seldom I met any locals that are unkind or rude and in most cases they are 10x nice than your neighbor. I also don't act like a jackass Cancun/Vegas traveler. IMO it's good to get out of your comfort zone.
How do you know a certain place isn't appealing if you've never been there and all you know about that place is what the media tells you? No doubt there are place that I loved and places that I was "meh". I have a friend that absolutely HATES Costa Rica which is beyond comprehension for me but each to their own.
Personally I get ill at the idea of going to a mega-resort in Mexico and hanging out with a bunch of other fat obnoxious Americans and eating at a buffet.