After Beppu, I took the bus in front of the train station to Yufuin (由布院) hot spring resort. It was a scenic 3 hour ride through the mountainous road. The winter light rain and fresh forest air made it a pleasant bus ride. The bus dropped me off directly in front of the train station in Yufuin-
I stayed at a traditional Japanese ryokan which has a cozy small indoor and outdoor onsen hot spring-
There is a small lake in Yufuin where you can walk around and enjoy the peaceful surroundings-
The main narrow commercial street is lined with cafes and souvenir shops-
Recommended length of stay for Yufuin- 2 nights
Here is my drone video of Beppu and Yufuin-