Keisei offers online discount tickets for non-japanese citizens.
I will be visiting Tokyo landing at NRT, so a return ticket seems to make sense.
However, I cannot find any info about the "return" part of the ticket. The online purchase system only has one "date of trip" field. You have to exchange you e-ticket for a real ticket at the airport.
Does that mean I have to choose a date/time for the return part at the desk on the arrival date? What if I miss the train on the departure date, can I board the next one?