There were two day trips we planned to do from Tokyo while we were there. One to see Mt Fuji (but not go to Mt Fuji) and one to the north to Nikko National park. We thought that we should be able to do the Mt Fuji trip ourselves on the trains, but the Nikko one would have been a little more complicated, and decided to get a guided coach tour for that. The tour group did hotel pickups from Shinjuku, but not ours. I’m not surprised I wouldn’t want to try and get a coach through the tiny street it was on. I rang them up to confirm the pickup location at Shinjuku Station, the hotel phones didn’t dial external numbers so I used Hangouts on my phone.
Before I had even gotten through immigration I managed to pick up SIM card with unlimited* data and was back online. I grabbed my bag from the carousel and headed towards the train. There is a customer service centre just after customs with a big sign that says “There are more places to buy your ticket, including the destination station.” or something like that. I bought a ticket anyway and head to the platform. Exiting the customs area and into the arrivals hall they have giant TV screens showing the other exits passengers can come out, just in case people waiting for you are at the wrong one they can see you.