For a quick getaway from Tokyo, Hakone (箱根) is just 70 minutes by train from the city. It is close enough to be a day trip but an overnight stay is best if you are seeking a brief and therapeutic escape from the big city.
Much of the area surrounding Hakone is part of a national park with spectacular views of Mount Fuji (if the weather permit). It is a resort town that boasts a number of museums including the Hakone Open Air Museum with its Picasso exhibit.
It is fun day-trip which combines rides on several trains or buses, funicular, cable car and enjoy a cruise across the peaceful Ashino-ko lake, surrounded by natural beauty and the view of nearby Mt. Fuji.
Explore the sights of Hakone on a 8-hours private tour with a professional knowledgeable guide.
An overnight stay at a Ryokan/Onsen is recommended.