TRISTAN: The police are letting our parents handle it, and in my case that means military school in North Carolina.
A meta comment. Chad Michael Murray, who played Tristan, left the show in order to begin filming the teen drama One Tree Hill (2003-2012), shown on the same channel as Gilmore Girls (The WB); Murray had the lead role of Lucas Scott. One Tree Hill is set in the fictional town of Tree Hill in North Carolina, and mostly filmed in Wilmington, North Carolina.
Amy Sherman-Palladino apparently planned for Tristan to become Rory’s boyfriend in high school/college and her “Christopher”, which, because Chad Michael Murray went to another show, was a role filled by the character of Logan Huntzberger instead. In this farewell episode, you can see the faint beginnings of the tenderness between Rory and Tristan which would have blossomed into eventual love. Anyone wishing to see what would have happened if Logan had been Tristan instead must turn to fanfiction.
In real life, there is only one one military school in North Carolina, and it is Oak Ridge Military Academy, so presumably that’s where Tristan is headed. It was originally founded in 1850, and was one of the first military schools to become co-educational, in 1972. It apparently had a reputation at one time of taking troubled youth, which it is working to overcome.
If Tristan turned up to Chilton in order to say he was leaving for military school, couldn’t he also have stayed to do the scene with them? Does everyone transfer schools on a Sunday night in this universe? (Maybe because they’re boarding schools?).
With Tristan out of the picture, the love triangle between Rory, Dean, and Tristan comes to an end, to make way for a new love triangle, which becomes clear in the very next episode.