We had a great stay on Milos at Maria's cave apartment. The apartment is outside of the main towns, but you can easily reach Plaka by walking ~10 minutes. The apartment itself is very unique and beautiful. The cave style also keeps it very cool despite the heat outside. Maria also picked us up from the ferry, which was very kind. I'd imagine the apartment might be tricky to find without her help, so I recommend asking for a pickup or detailed directions before your stay. If you're looking to stay a bit off the beaten path in Milos, Maria's cave apartment is a great option.