Mid-March is probably a bit early for cherry blossoms in the main areas of Tokyo and Kyoto. Kyoto will have plum blossoms and a few early varieties of cherries but the really splashy displays are likely a bit later. On the other hand, with global warming, things may start up a little earlier.

For food and shopping, you might want to consider Osaka and then day trip to other locales for nature. Or perhaps go on down to Hiroshima and work out from there. They tend to start the blossom season a little earlier. I would probably go all the way down to Kyushu and stay in Nagasaki or Fukuoka but that might be a bit far afield for someone who is not familiar with Japan. Since you have been there before, you might want to consider it. The cherry blossoms start weeks earlier on Kyushu.