I have booked my hotel at InterContinental Yokohoma Grand. Tips will do too, anything that might be helpful. Thanks alot.
That's all up to your interests.
But one of the better museums is the Edo-Tokyo Museum.
There are also 4 big national museums, like the Tokyo National Museum, the Kyushu National Museum in Dazaifu, Fukuoka, plus in Kansai the Kyoto National Museum and Nara National Museum. There are countless more that vary by subject - natural history, dinosaurs, insects, folk life, western art, Asian art, etc etc.
If you are staying in Yokohama, the Sankeien Garden is right there and one of Japan's best. Tokyo has lots also. See:
For food, try http://www.bento.com