[MMM]

If you are staying in Tokyo, you won't want to waste money on a train-pass. You probably won't use its value daily. You want to stay on the Yamanote Loop line, but if you are out until 5 AM you can find cheaper accommodations outside of Roppongi and Shinjuku (I am not a Roppongi fan) I like Ueno, as there are nice and cheaper hotels near the station.