You can also set the resource path to a known directory (like the standard asset directory, if there’s such a thing for iOS). That way you can always be sure that your data will exist at said location.
See CCFileUtils for more about that (afaik it was something like “setResourcePath”, don’t have the code with me right now).
Unfortunately, it’s not possible (to my knowledge) with current Cocos2d-x to set multiple resource paths and have resources automatically searched in those paths. That would be really nice to have.