Hi,

I was going to suggest a few gardens close to the toyko monorail station at Hamamatsucho ( there is also the Seaside top observatory on the 40th floor beside the station open till late IIRC) but they close arounnd 430pm and the zojoji temple close to tokyo tower closes at 5pm. There are outdoor observation decks at Haneda . At Tokyo station you could visit a few of the rooftop gadens ( I went to the KITTE building one whixh was interesting) , go to the plaza in front of the Imperial Palace or make a quick visit to Ginza.

Regards

TBS