Thomas Lee
Google
We had an amazing room with a private outdoor bath, which had constant hot spring water, and great view. The bathtub was just as hot overnight to the next morning. Plenty of amenities to try in the bathing area as well that we didn't use the public hotel baths. The room also came with the lounge access, which had a good variety of food and alcohol. If you are visiting Kusatsu as a couple, I'd definitely recommend having a private bath as mixed gender public baths are limited.
The only downside, in my opinion, is the breakfast and dinner. It's all buffet, albeit a wide variety of food, in hindsight we would have preferred to skip it and explore the area instead.