The apartment that Niles (David Hyde Pierce) rents is a set that was reused as Robert Barone's (Brad Garrett) apartment in "Everybody Loves Raymond (1996)."
When instructing Martin on how to access the secret passage in his apartment, Niles tells him to "Poke Mrs. Dalloway on the bottom," referring to a book on the shelf in front of him. "Mrs. Dalloway" is a novel written by Virginia Woolf and first published in 1925.
The episode title, "How To Bury A Millionaire," is a play on the title of 1953 movie musical "How To Marry A Millionaire."
The bed Frank folds out of the wall at the Shangri-La is nicknamed a "Murphy Bed." It is named after William Lawrence Murphy, an Irish immigrant in New York who wanted to find a creative method of making space in his apartment. His received his first patent for the bed in 1912 and another in 1916.
The exterior street and car scenes at the beginning of the episode were actually filmed in Seattle. The opening shot was filmed on Pine St. between 5th and 6th Aves. The second shot, where Frasier and Martin turn the corner to follow Niles, was at 5th Ave and Pike St. The implied route, inferred from the visuals and dialogue, would then be: heading west on Pine St; turning south on 2nd Ave, where they called Niles; turning left on Pike St until they reached 5th Ave: and turning right to head south on 5th Ave.