I used to live in Juan Dolio for a year. Around 2016. I'm American as well but not white. I can blend in a little more at times.
My experience was good. Safe, I hung out on the blvd many nights. Having a beer, eating, or just chatting. The beach isn't so great in my opinion. You can get robbed anywhere in the Dr. I've lived here for quite some time and find it to be safer as opposed to a few years ago. Most of it just respecting other people when you get to town. Make good with the colmado people, your security guard in your building, and the community who wants to maintain a relationship. There's a wonderful Swiss lady with a bar and restaurant. It is calm and relaxed. There used to be a margarita place there that closed.
The issue is some seasons are really hard on local businesses there. It's mostly dead in the week. The weekend you have people from the capital who come to their condos (or their kids)
I do know stories of robberies of larger homes. Those people aren't around anymore, or should i say attempted robberies? I would have security if i had a home here. I personally feel safer in a building, but you miss out on your space.
All in all, it's a decent place. Prices for rent are fair. Buying, however, is expensive to me for the towers, I am not sure why as there is not much to do there. There's a gated community called metro. They have some reasonably priced apartments there (for a gated community).