If there are guests for CN on the shuttle, they would make a stop there. It does not take long and does not effect the travel time to CSA. The other two resorts are in the opposite direction, so the shuttles to CSA would not be taking guests going to CTI or CSS
It may stop at CN, but only if there are couples on board who are staying there. CSA is about a 7 to 10 minute drive beyond CN, so even if the shuttle stops, it's a quick drop off and then a very quick trip to CSA.
I dreaded the shuttle when we went to CSA until I got on the bus and actually had a great time! The time flew by and we met some great people, enjoyed the countryside, and had a few laughs with the driver!