Debbie, nothing more for me to do; I was going to check schedule. You should have no problem making the one at 3pm assuming no problems at security. I would hightail it off the plane though.

Subway now has signs in english. Machines to buy tickets also have english. Some outlying stations don't have much english but you should have no problems. The hotel will give you a card with hotel address in Japanese. Very few taxi drivers speak english. Also, most taxi drivers in Tokyo don't know their way around Tokyo.

There is lot to do walking around Imperial. You are also convenient to both subway and trains.

Don't forget your walking shoes!