I stayed there a few days ago with wife as a Plat Ambassador, and was upgraded to what the clerk called a double room on the top floor. It was not a suite, but is plenty big for two people.

It is very easy to get to Shinagawa Station, expecilly on the N'EX from Narita. I used to stay at the Tokyo Bay Intercontinental when arriving at Haneda, but I've decided Strings is better. From Haneda, I would take the monorail to the end, and then walk into the adjacent JR station and go on the JR circle line local train a couple of stops to Shinagawa. (The Tokyo Bay Intercontinental is only about a three block walk coming out of the monorail station. Strings is actually about the same amount of walking because the Shinagawa JR station is so huge.)

The trick is to find The Strings when exiting the station. Take the east exit (Kanda). Stay on the elevated walkway. You'll see two very tall buildings connected to the walkway. Walk to the one on the right. Continue to the middle of the building. Walk past the mini 7-11 shop into the building. Turn left down a short corridor. Take the elevator up to the check-in. There is also a map online showing how to find it when coming out of the station