For suggestions on how to continue your journey, see Alternatives.
Biwa offers a lot of surprises, often in unexpected places. Speeding down a western coast toward the city of Otsu and the train home, I passed this very creative billboard for what is apparently a children's amusement park and outdoor recreation center. Since it's about 20km from the lake, I decided to leave it for a future journey.
The "find" of this trip was definitely this spectacular windmill. Elsewhere there's even a fake Dutch village, complete with tulips. Every time I go to Biwa, I seem to find something new and unexpected - and that will keep me coming back, whether it's warm enough to swim or not.