Stay at Osen ryokan
Ryokan is a Japanese style inn where you sleep in futon and have beautiful Japanese kaiseki cuisine for dinner, plus onsen! Hakone is one of the largest onsen district throughout Japan and it is impossible to miss the experience at onsen. There are also many foot bath where you can casually experience onsen.
Go to museums
There are lots of great museums in Hakone, such as Hakone Open Air Museum, Venetian Glass Museum, and Little Prince Museum.
Hakone is one of the most famous Onsen(Hot Spring) areas in japan. So Onsen is a must! And staying at Ryokan which is traditional japanese style hotel, you can have a heartwaming japanese service OMOTENASHI at Ryokan.