I booked the Marroad International Hotel Narita directly. Initially although they showed Runway view rooms, they could not be booked, but 3 months to the day before the trip they became bookable. I had room 1296 and the view was excellent from the 12th floor. A selection of photos can be found here on Flickr.
In the morning, I actually decided to stay in the room for an extra hour taking pics, rather than going to the T1 deck at opening time. Overnight they had changed to arrive from the North. The room only allowed arrivals and departures on 16R to be seen so eventually I needed to leave. But it should be pointed out the breakfast was on the 13th floor and from there it was possible to see both runways. So, you could also probably enjoy a few beers in the evening up there in the bar/restaurant.
https://maps.app.goo.gl/rfGAtf6pTKjvqVeQA
Breakfast room view of 18R threshold.
View of cargo ramp from room.