You can take the Tobu Bus from JR or Tobu Nikko Station, and get off at Chuzenji Onsen Treminal, for a total 40 min ride. Thereafter, the Kegon Falls are a short walk away.
Shirakawa-go Village
You can travel to Shirakawa-go by public transport or rental car. From Tokyo, a one-way high-speed train costs 13,500, and