I bought Exodus from GOG just two days ago. The core C3 game doesn't require an Internet connection to play, but like the poster above me said, Docking Station requires you to be online to register your new world for the very first time (after which you can play it offline without any problems).
If you're buying Exodus, there's an option to run a "docked world" (which connects the C3 and DS worlds seamlessly together), so this may be applicable to you. However, like I said, you only need to register your world with the DS server once.
If for whatever reason you wish to create a new DS/docked world and you lack online access, the aforementioned 3rd party tools can help you out.
PS. All the links for the original "DS Login Disabler" are dead. I've got a copy on my HD, so if you want it, let me know. It's also worth mentioning that C12DS, an add-on for C3/DS that recreates the first Creatures game for the C3 engine, contains the offline-world functionality by default.