You can take the train from HND and be in several different places within 15 minutes depending on what you want to do. You could probably be anywhere within the Tokyo metro within 30 minutes. Just be careful to return before midnight as trains may no longer travel late at night. Maybe even plan to get back by 10:30pm just to be safe. Don't bring any bags with you, put them in a locker at the airport or train station so it's just you with your passport and valuables. Since it's 4:30 pm you will catch rush hour traffic when you arrive so be prepared for some packed trains.