There is a nice place to visit in spring nearby Tokyo – Odawara. It is directly reached by train from Tokyo and perfectly suits for one day trip. Odawara Castle is one of the many interesting places in this area. I publish just one picture I really like.
Other popular tourists spots are: Ishigakiyama Ichiyajo Historical Park, Kanagawa Prefectural Museum of Natural History. Detailed description of the Odawara highlights as well as events schedule can be found here.