Originally Posted by
evergrn
In fact, forget about NEx because that means getting off at Shinagawa and then transferring to the commuter-style Keikyu train at Shinagawa most likely around 5.30~6p. I recently took that Keikyu train with suitcases in tow in the evening... it was brutal.
I think N'EX to Shinagawa + Keikyu to HND is pretty good. It's efficient and cheap (if using N'EX + Suica intelligently).
If heading to a midnight departure from HND, the OP can leave luggage in a coin locker at Shinagawa. Explore Tokyo. Come back to Shinagawa and catch an evening service to HND. No need to get on a rush hour train.