Writing this in English, since there doesn't seem to be a review in this language yet. This house is even better than the photos. You can tell it's a house that a family cares about and uses itself and it has interesting art and decor you wouldn't normally find in a vacation rental. The house is located right on the edge of Riaza, looking straight out over the countryside to a spectacular view of the mountains (Sierra de Ayllón), especially in the afternoon. It's the perfect spot for a big family or group of friends who want different spaces to hang out and not always be in each other's hair, both inside and outside. We were eight people, but there could have been a few more and it would have been fine. There's plenty of room for up to ten people to eat together inside or outside.
We were worried about the August heat (it was one of the hottest weeks ever in Riaza and it was just unbearable 24/7 in Madrid), but the house is well-designed to have lots of shady spots, with shutters to keep out the heat during the day, and cool breezes from the mountains and good ventilation at night. No AC necessary, though we did bring a fan, just in case.
The garden is really lovely, with green grass, roses blooming and lots of birds, even during the hottest part of the summer. Be sure to sit out on the back terrace at night to look at the stars--since it's the last row of houses, there's very little light pollution.
Everything in town is within a 5-10 minute walk. The list of suggestions for restaurants, food, and places to go in the region was great. Antonio was a wonderful host and was available for anything we needed. Don't miss ordering lamb from the butcher and taking it to the bakery to roast it (platters in the house). Riaza is a great place to base yourself to hike in the nearby mountains or drive around to see the nearby medieval towns like Madriguera, Maderuelo, Sepúlveda, etc. Don't miss the walk through the Hoces del Río Riaza or a trip up to Puerto de la Quesera, where there are many hikes you can do, even on the hottest days.