All of the scenes taking place at the park bench were shot in a small soundstage in Flagstaff over the course of two days.
The original draft of the screenplay all took place in a single location: Ra's. Most of this version took place with the characters sitting at a table where they played a psychological game a chess. However, this version was pitched to a studio but wasn't picked up because the studio wanted to see more. After that, the script was rewritten to include multiple locations. The exterior of RA's is still in the film briefly but the characters never go inside.
Much of this film is based on the real experiences of the writer/director Nick Hiratsuka. Everything from the Caffeine addiction, insomnia, and locations they visit, to how the relationship ended, the regrets around the graduation party and even the blue crown with the message inside were all based in reality.