It was an amazing stay and Kanako-san is a wonderful host, I am very grateful!
The only problem was indeed the cold, especially if one has to close the door to the room and stay at the kitchen (e. g. when someone's sleeping in the room). There's no source of heating in the kitchen, and wind's coming right inside through the gaps around the entrance door.
Apart from that is was a very nice stay, the local area gets amazingly beautiful at the and of March.