Martin was a very kind and considerate host, was very friendly and eager to chat. Martin even made us breakfast to "make up" for the cab ride that we had to take to the house (we arrived after public transportation stopped running). The house is in a very quiet village with a nice view. We were offered a room inside the house because the trailer had a water problem. Inside the house there was also a water problem, and there too we shared the communal bathroom, which was no problem.
Important note: The taxi fare to the house from Sintra in the evening time (the only way to get there) was 15 Euros. We thought it was going to be far less and were a bit surprised.
Another note about public transportation: The public transport from/to Sintra is not very good. When we were ready to continue on our journey, we ended up waiting about an hour for a bus from Sintra back to the house, and then another hour for the bus back into Sintra! The conclusion is, if you have a car - or if you have a lot of time to spare - this is a great place to stay. If you are relying on public transport and don't have much time, transportation may eat up more of your day that you would like..
In any case, thanks to Martin for a pleasant stay.