Communication with Maria was very good in advance of our stay, and Mariella who runs the shop below the apartment was extremely pleasant and helpful during our time in Trecastagni. The apartment is beautifully furnished, with a lovely private courtyard: the perfect place for a sunbathe or dinner.
Trecastagni has all the food shops you will need, and a good bar 150m away. Although the Catania side of Etna is quite built up, there is a great view from Trecastagni to the sea, and we were well placed for Etnaland (1hr away).