First of all: We had a great time. And can recommend Casa Mariannina fully.

The Apartment:
Rosas Place is small but thoughtful equipped. Neither did we miss space nor any furniture or conveniences. There is a balcony large enough for two people to have dinner on. When we arrived it was spotless clean and already equipped for basic need. The house seemed to have just been renovated, so everything looked in good shape.
The place is situated only a few minutes away from Castellamare del Golfs old-town center and the bay. Next door is a small bakery, open 7 days a week. Larger stores (and markets!) are reachable by foot.
It should be mentioned that although the center is very reachable the apartment is in a quiet back alley. Very good.

The Host(s):
Especially Rosa and her husband were very helpful, yet respectful of our privacy. When we arrived we got a bot lost in Castellamaro as our map was a bit older. (google maps will be fine though) - one phone call later they rushed to our rescue. Later on they recommended their favorite markets, restaurants and cheese vendors to us.

Castellamare del Golfo:
The town is a beauty (especially compared to other options nearby) with lot of flair, good, affordable restaurants and an "embedded with the locals" feel. We went into town every night and enjoyed the strolls through the small alleys and large pedestrian zone. Everything is very good illuminated and we felt safe the whole time. If you are looking for a nice base camp to start day trips from in western sicily: We can recommend Castellamare del Golfo.

The Surroundings
The Zingaro Reserve, a couple of nice beaches, Scopello (why would anyone go there?), the Airport and Segeste feel nearby by car (recommended). To Trapani, Palermo, San Vito lo Capo and Erice are reachable within one hour by car.