Kawaguchiko is just over the hills from Hakone
Hakone of Lake Kawaguchiko? Which to choose? It is easy to get from Hakone to Kawaguchiko by bus. You can do both because they are relatively close to one another. Kawaguchi has some amazing views of Mt. Fuji, but Hakone is a more balanced experience because of the the history, culture, and traditional hospitality found in the area.
Hakone and Lake Kawaguchi are only about 80 minutes apart from each other by bus ride along the base of Mt. Fuji. The bus ride is nice and gives you chance to see some of the nature and mountains of Japan.
Convenient buses will get get you between Hakone and Kawaguchiko
The Fujikyu Bus company runs buses from Kawaguchiko Station to Gotemba Station. From Gotemba Station you can ride the Hakone Tozan bus over the hill to reach the Sengoku Highlands of Hakone.
Going from Hakone to Kawaguchiko is just the opposite. Make your way to Gotemba Station by Hakone Tozan bus line and then change to the Fujikyu bus that will take you to Kawaguchiko.
One of the best options for this route is the Odakyu Fuji Hakone Freepass. This pass will allow you access to transportation around Hakone and Mt. Fuji, including a bus trip to or from Tokyo. You can not use the JR Railpass for this specific route. There might be some interesting things to see in Gotemba as well, the Premium Shopping Outlet, Whiskey factory, and various amusement parks in the area.
