Provided that everything is on schedule, you will have enough time to go out of the airport and visit Tokyo and come back. I think it's a lot better than staying in or near the airport.

If you want to take a train, Narita Express or Keisei Skyliner is better than regular trains in the morning, which will be picking up all commuters along the way to Tokyo. Since they begin at NRT, you can take a seat but they will get crowded very bad.