This was our first AirBnB and it was a-ma-zing! There are 6 houses on the domain, spread out on the hill in between the trees, so it feels as if you have the whole place to yourself. The swimming pool is below, not far from the river. And it's a 5 minute walk to the beach (at the river, not the ocean ;) ). Access by car is through a narrow road, but even with a large family-car, this poses no problem. Porto is a little over 30 minutes. The owner, Antonio, was always very nice and helpful.
In short, a real gem on the Douro river.