Wow! What a wonderful experience at Biwako Grand Hotel. Truly the most relaxing part of my Japan trip, the onsen was very beautiful, with fantastic views. We didn't end up getting a pure lake view, but it was still a beautiful and relaxing experience in the tatami room. It was a tad pricey, even for off-season, but with a wonderful kaiseki dinner, it was still a great time.
The room itself has a bathroom sink which is pretty convenient. Not expecting much given the price but it did have everything u need for a basic sleep.
Surprisingly the public bath is just hot water not onsen.