Cherry Blossom 2016

My husband and I will arrive to Tokyo (Narita airport) at the end of March 2016 and we are planning to travel to Kyoto and stay there the weekend for the cherry blossom. We will need to be in Shonan for my husband's work following Monday, but I am free to visit Tokyo and areas around until our departure ( a week after our arrival to Tokyo)

We plan to use train or bullet train (if needed from Tokyo to Kyoto to save time since it will be a short stay in Japan). Your advise on what kind of train pass to buy and where to visit around Shonan or Tokyo is greatly appreciated.

Thank you.