Tokyo and Narita should be the same airport (check the airport code NRT).
In terms of what to do in Tokyo, that really depends on what you are into.
http://www.japanforum.com/forum/japa...-go-tokyo.html
http://www.japanforum.com/forum/japa...725-tokyo.html
http://www.japanforum.com/forum/japa...ide-tokyo.html
I would consider the fact that if you want to work out all day, you can do that at any hotel. If your companions want to explore, they might resent having to travel 30 minutes by train (give or take) to see sites, when the other hotel you mentioned is in the middle of the action. But that's the last I'll say on that.
Go to the website of the hotel and you can see links in English to traveling around. There really couldn't be more information out there.
Must-see and must-do in Tokyo! | Ask Metafilter