I'm going to be trying this for the first time next week. Have a late arrival into HND (international) and while they have some basic directions about how to access the place after hours, I'm curious if anyone has any additional hints/tips/guidance?

This is what they provided on the confirmation email:

※Domestic Terminal 1 is closed after 23:30.
For check-in after closing, you should come to the service entrance only for night around the Keikyu Bus stop No.8.
When you call us with the intercom, we'll take you to our hotel.