Trivia: In the Turtle's trophy room, there is an Ooze canister on the shelf. In most incarnations of the TMNT, the company on this canister is labeled TCRI, but in the second live-action movie, it is TGRI. According to the director's commentary, they have the canister here split in just a way that you can't tell if it's a C or a G, helping to leave it ambiguous if this film is part of the 90s movie continuity, part of the 03 series, or its own continuity.
Trivia: Mikey Kelley is the voice of Michelangelo in this movie, and he was the original voice actor for Ratchet in the first Ratchet and Clank game. James Arnold Taylor is the voice of Leonardo in this movie, who replaced Mikey Kelley as Ratchet in Ratchet and Clank 2: Going Commando, and onward. So both voice actors for Ratchet play two different Turtles in this film.
Chosen answer: Because unlike everyone else, they know EXACTLY where it is! They are their friends, of course they know how to get to the turtles' home easily.
Carl Missouri