As the name states, Business Hotel Serikawa is a business hotel, located along the Serikawa River. The hotel has Japanese-style rooms, in which you sleep on the floor on a futon, and Western-style rooms, which have beds. As long as rooms are available, you can choose the type you prefer. Prices are quite cheap, as you will likely pay between 4000-5000 yen only.
From the hotel, you can approach Hikone Castle from the district of preserved buildings, which is the best way to do it (if you go directly from the station, you would just go through the city).
2-8-4 Kawara, Hikone
155 Furusawa-cho, Hikone
111-3 Higashino Namicho, Hikone
1-8 Sawa-cho, Hikone