Hi Robyn,
Check out
Owen's Notes on Tokyo on Slow Travelers web site. It has a lot of helpful information on visiting Tokyo. His tips are very good. He has information about the airport and getting around. I also used the Airport Shuttle to get to my hotel. They have a stand right outside of customs. I returned to the airport via the train and was with a coworker who helped me. That would have potentially been a little hard for me to figure out on my own. If I had not been with the coworker, I would have probably taken the same bus back to the airport.
I visited Toyko on a quick business trip a couple of years ago. I also had a short time to visit. I stayed in
ANA Hotel which is located in Akasaka area. There were many multi-national companies offices in the Akasaka area. The hotel is in the mid-high price range.
I was working during the day so I spent the evening sightseeing. It was about a mile from the hotel to Roppongi area which was lively at night. I was able to walk to the area from the hotel although part of the walk was kinda boring along the offices and under one freeway.
The next night, I took a bus from the hotel to Shibuya. This area is a lot of fun. Very bright, noisy and lively at night. A great place to people watching. I loved checking out the young people and their style of cool outfits. There is a large department store and a pedestrian area lined with small shops, restaurants and pachinko places. If you get a chance, you should try to visit this area. It is also a major transportation center so there is great access for subway, bus, train and taxi. I took a taxi back to the hotel. I recommend always carrying the name and address of your hotel in Japanese in case the taxi driver does not understand the English name of your hotel.
I also recommend taking a 1/2 day bus trip of Tokyo. I booked the tour at my hotel for an English guided trip. We went to the Imperial Palace, a Shinto temple, and the Buddhist temple at Asakusa. The trip was around $40US.
You may also want to pick up a small city travel guide. I found the mini Rough Guide for Tokyo very useful.