Could you be more specific? which file do you try to access? did you already save it?
1/ For your main problem: you can create a dictionnary or array with a file path
[NSDictionary dictionaryWithContentsOfFile:<#(NSString *)#>]
[NSArray arrayWithContentsOfFile:<#(NSString *)#>]
2/ But you can, as you wrote it, read the "string" content from a file and then, eventually, parse it. For that you need (for example) a path like this (for the "directory" dir, could be the "cache" dir)
NSArray *array = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *pathToFile = [ [ [ [ array objectAtIndex:0 ] stringByAppendingPathComponent:@"nameOfTheFile" ] stringByAppendingString:@".ext" ] retain ];
And then use "pathToFile" in my 1/ example.
3/ For your internet access, I recommend you to check AFNetworking. It's better to do async download ;-) (yours is synchronous)