"Grand Prince Hotel New Takanawa" has a balcony in every room.

No, you have to take JR to Tokyo station (M17), where the hop on/hop off office is located.

I do not know.

If you make a reservation at the hair salon in the annex, we will respond.

Not.

In Japanese please!

You can but the better option is to catch the Narita Airport Express train (NEX). That will take you to Shinagawa Station and is covered with a JR Pass. The hotel runs a free shuttle bus service every 20 minutes to and from Shinagawa Station or it is a 5 min walk.