Thanks for your feedback Emily. Our rainy season is September and October, not May to mid-November.
Unfortunately during rain storms the power does go out everywhere., This is common not only in Costa Rica, but worldwide.
Casa Coco is located minutes from the beach in the jungle on a dirt road and yes we do not have street lights - that's the beauty of the area! It's amazing the stars you can see without light pollution. Sorry it was not close to a city for you, not only is Nosara located in a Blue zone, we are on a national reserve meaning that it will never be built up with high rises, large hotels on the beach or highways.
The sun sets at about 5:30 which is the busiest time on the beach as each you'll see some of the most incredible sunsets ever! It's unfortunate you found that scary.