Hakone is an area in Kanagawa Prefecture known for its volcanic activity and natural beauty. There are hot springs, lakes, and mountains that appeal to hikers, and museums, shrines, resorts, and restaurants for those seeking cultural activities. Mt. Fuji towers over the area, visible on clear days and adding a magical beauty to the region. Not far from Tokyo, it attracts hundreds of thousands of visitors a year and is included in many tour packages.
Because there are so many things to see and do in Hakone, many people prefer to stay at one of the hotels, though it is possible to visit many of the attractions on a day trip. There are seven hot spring towns in Hakone so finding the one to stay at can be a challenge as they are all beautiful. The seasonal changes make the region interesting to visit year-round.
Many tourist spots in Hakone can be reached by riding the Hakone Tozan Railway. The train repeats switchbacks three times to go up the steep slope from Yumoto, the entrance of Hakone, to Gora as it is a very steep climb. The train ride is beautiful and much of the valley of the Haya-kawa River is visible through the lush vegetation during the trip.
For an excellent list of the tourist attractions, access information, and other useful details for a visit to Hakone National Park:
http://www.hakonenavi.jp/english/basics/