User blog comment:Menara/The Son of Sobek: The official PJ and Kane Chronicles Crossover/@comment-124.180.218.120-20130315080212

Considering Percy's age, the fact that he remembers/is around long island, and isn't in Tartarus certainly means that this takes place during the interval between the end of The Last Olympian and when Percy was kidnapped. However, just from what Carter gives us in this exceprt, it's impossible to say exactly when in his timeline this is. I'd say either between Throne of Fire and Serpent's Shadow, or simply completely after the Serpent's Shadow. He doesn't mention Apophis at all, and seems more at ease in New York, so maybe after the Serpent's Shadow.