Yes, Couples does offer shuttle transportation between the resorts. We went for our first trip this past March to SS, and loved it so much, we made our next trip a split between CN and CSS next april/may. I believe it is quite a haul, though. From what I have heard, it is close to a 3 hour drive. The other option is to charter a flight through TimAir or AirLink from the Boscobell (sp?) airport near CTI/CSS to the Negril airport right across the street from CN. It is a 40 minute flight instead of a 3 hour drive. We are looking to find people to share this flight with us, to split the cost. When I spoke with TimAir, they said if we have people looking to go both directions, we can all split the cost, since TimAir would have to fly back to Negril or Montego Bay anyway.
I think I read on here before that they will do the transfer. I think it will be a rather long drive though. They may take you to the airport and then you catch a transfer from the airport to CN if that makes sense for you.
Yes, Couples will provide transportation between the two resorts at no cost to you. Just let them know at check-in of the first resort so they can plan on it. You can select the departure time. Have fun!!!