Where to go for hot springs, go for a ryokan. Kurokawa is very famous, but there are many tour groups in Korea, so the next Shirokawa might be better. Other than hot springs, we recommend Kaisen-dong and Takasakiyama nature park.
It was a good place, but there were some places that I thought were dangerous for traveling alone at night. There are many shopping streets in the Oita area and lots of places to eat. Nishitetsu Hotel is a very good hotel It was delicious because there was restaurant of tongdong. If you find out about Mirent and go to nearby Yufuin, it will be a better family trip ^^
벳부 의 온천은 대박 기회가 되면 료칸에서 머물고싶다.