The building used for the climactic action at The Grant Hotel was the famous Hollywood Tower Apartments building (about 15 years before it was named an historic landmark).
Barnaby keeps a bottle of bourbon stashed in the back of a file cabinet drawer.
Katherine (Lynne Marta) says her husband met Charlie Cort (Glenn Corbett) in Cherry Point, North Carolina. That is not a city, but is a military base, the home of the US Marine Corps 2nd Marine Air Wing. It is in Craven County, near Havelock, North Carolina.