We went to Naxos off season and I highly recommend to stay in this place. It's just meters away from a bar/restaurant called Kahlua which was open everyday compared to most of the bars and restaurants along Agios Prokopios that were closed. Since there weren't many people, we were allowed to use the sunbeds by the beach and this was really nice.
Heike was such a delight. She's very approachable, welcoming, and thoughtful. She made us feel home and was always there in case you needed anything. Konstantinos, her son, responded really fast as well and was very efficient.
If you come to stay in Agios Prokopios, off season or not, I do believe that this is the place to be.