Does anyone have advice on how to spend the night between 10:30pm HND arrival and 10:30am NRT departure next morning? The timing is inconvenient enough that it seems infeasible to see anything in Tokyo very much. Cost of a hotel reduces the appeal of this deal - but maybe there are clever options about how to pass the time?
And on the way back, 7am arrival NRT, then departure 5pm NRT kind of suggests not leaving NRT.
You could take public transportation from HND down into Shinjuku. It will be packed though since that is around the last time that trains run.
I would probably stay at a capsule hotel ($30-$60 USD if I am not mistaken). Its a unique experience and being right in Shinjuku, there should be plenty to do at night too.