This is pretty remote... take the train to the end of the line, then take the bus to the end of the line! You're in deeply valleyed mountains (tho' still, believe it or not, in Tokyo prefecture!). Yamashiro is at the top end of the price points for a simple rural ryokan, but it has some unique advantages.
The basics: it's a nice old wooden building, traditional and welcoming. The lady of the house does what you'd expect in a ryokan, explaining everything and taking you to your room, while her husband checks your mealtimes and departure bus. The room was more of an almost-suite, with a nice sitting area by the window (with a bug screen so on a cool night you can sleep to the sounds of the forest or the gentle rain), and a separate washbasin and toilet. There's no bath but... you don't need one. There are only two guest rooms, and two baths, so you have your own Japanese bathroom! The rooms were classic Japanese style (seen one, seen a thousand) but in good condition, and with mattresses under your futon which were surprisingly comfortable. Of course there's tea and cookies. There's also free wifi if you really have to work or check the football scores.
The bath was wonderful, just nice for two people to share.
You also have your own dining room. Dinner was a good kaiseki, not exceptional, but very good, with plenty of local produce. Breakfast was similarly good but not unusual. Service was excellent, and the young wife of the household was a superb hostess, both professional and friendly.
Although the other room was occupied, we didn't see or hear the other guests until the morning when we checked out at roughly the same time. It was almost an exclusive experience, and, with two rooms, I would imagine that it nearly always is.
The experience is fundamentally the same as any other well-run rural ryokan. The differences are small but they add up (wifi, mattresses, large room, own bathroom, own dining room) and the overall experience is a good couple of notches better than you might expect, just about justifying the premium price point.
There were no real negatives, except that unless you value almost-exclusive privacy, it's a bit expensive. And we came by public transport, which is fine point-to-point, but a rental car might have afforded a bit more flexibility to explore the area.
