Anson Mount was initially reluctant to accept the role of Ben - finding the script to be "cheesy" and "lame" - but was encouraged by Robert De Niro, with whom he was working at the time on City by the Sea (2002). De Niro turned out to be a huge Britney Spears fan. They went over scenes from 'Crossroads' on breaks from 'City by the Sea,' with Mount reading his lines and De Niro reading Spears'.
According to Kim Cattrall, the role of Lucy's mother was originally intended for Madonna.
Dan Aykroyd created a detailed back-story for his character and his life in the navy. He even had a friend draw a navy tattoo on his arm (which can be seen in the scene where he is working on the car in the garage).
In the scene where Mimi, Lucy, and Kit are partying in the Louisiana Hotel room, you can hear Britney Spears accidentally shout "Zoe" at Kit, played by Zoe Saldaña, when they are laughing about a dirty subject.