Sarah Hyland's (Haley) boyfriend at the time, Dominic Sherwood, was in this episode, as Alex's love interest.
Haley mentions that she was on a train in Vegas, referencing when she and Andy went to Vegas in Express Yourself (2016).
Geography teacher "Cindy" implies to Luke that "Big Sur" is a sight to be seen from the train, but no Amtrak (or any other) rail lines pass anywhere near that part of the California coast.