How frequent are the buses? I guess It's OK if your arrival is conveniently timed.
- Monorail leaves every few minutes. Connection to JR Yamanote Line at Hamamatsucho is relatively painless. That would be my preference.
- Option B - Take a Keikyu train that connects through to the Asakusa Line. Get off at Nihonbashi and hail a cab or walk (400m) from there.
- Option C - Taxi all the way.
Don't plan on taking Monorail + Taxi . Construction work at Haamatsucho station makes it a pain in the ... to get from the monorail to the street.