We stayed in this ryokan for two nights in May. The first night we were in a riverside room that is one of two in that wing, having a shared toilet. The second night we had "Sakura 2" which has its own bathroom, toilet, and hot spring bath. The cost is around 40000jpy per night for a couple, with breakfast included. Dinner is another 5000 yen each.
The hotel itself is a registered cultural property so it is worth the money just for the experience. On top of that though the rooms are huge, with nice views (at least in the cases of the rooms we had which overlook the river).
There are two main Onsen, one has big pots and the other a grotto type with tiles which looks to me like a 1930s style. Both are nice. The water is good, not smelly. There is also a small private bath and then the bath in Sakura 2 which is excellent.
The food is very good, and served in your room. Portion sizes are good.
The staff are lovely and helpful, we really enjoyed their company.
Location wise, it is at Tonosawa which is a few hundred meters from Hakone Yumoto but essentially you could be a million miles away in terms of better ambiance. Really nice. A tip is to walk from Hakone Yumoto rather than getting off at Tonosawa, as it is about the same distance and easier with luggage. If you get off at Tonosawa you have to come down a steep hill pathway then cross a road to get to the ryokan.
It is isolated enough to be away from the touristy part of Hakone, you could be in Kurokawa Onsen for all that you would know, but with the advantage of a bustling town a few minutes away.
All told, an amazing experience.