a few random ideas
Odaiba - near Shinagawa. Lots of museums, malls, some nice nature walks too
Tokyo Disney Land/Sea
There is a huge aquarium near Shinagawa
go to Ueno and walk near the train tracks - Ameyoko
Yokohama for the amusement park, mall
Kamakura for history
Enoshima - little island, 1 hr from Shinagawa
imperial palace
kabuki
asakusa
go to minowa and take a train trip on the toden (trolley)
harajuku
shibuya
go to Ginza and walk around
akihabara
asakusa
daishimae near nishiarai
....Japan, like a lot of places, is rough without friends. hope you enjoy yourself.