One of the female authors seen in portraiture - J.Q. Guintel - is clearly a female version of series creator J.G. Quintel with transposed initials.
Rothgar - the protagonist of The Rigid Helmet - is extremely similar to the default Barbarian Class Character from Diablo Immortal. The only differences are that Rothgar is younger and has a giant sword instead of the Diablo character's giant axe.
The episode's title is a reference to the 2012 novel Where'd You Go, Bernadette.