The arrival:
You can easily organize a transfer from and to the airport with the owners of the house, all 8 of us could travel in one big car, it cost 30€.
The house:
The house is lovely and it looks exactly as it does on the photos online. It has got a nice kitchen, in which it's easy to cook. The terrace on the roof is amazing, great for cozy summer nights with friends or family. There is a huge cellar, in which you can be a bit louder even later at night (no parties, but stuff like talking loudly with friends and listening to some music). There is air conditioning in the whole house, although some of the air conditioners started dripping after about two days - no big deal though.

The area and the center:
There is a supermarket nearby (2-4min walking), which offers everything you need and there are some local little restaurants in the area. The house is about 40min walking distance from the center of the city, but you can take a bus (Nr. 7 from the station Av. Arroyo de Los Angeles (Parque Victoria Eugenia) to Plaza de la Marina, which is pretty much the center. The drive takes about 13min and the buses are (surprisingly) usually punctual. Sergio, who welcomed us at the house showed us some great restaurants and attractions which we could go to.
The castle itself isn't really that historically interesting (especially if you don't speak Spanish because everything is written in only Spanish) but the view from up there is magnificent, so it's definitely worth a visit.
Enjoy your stay!