I have not been to the Westin on Awaji Island, but it will take you even longer to get to than the Sheraton Kobe and there is no train service… and probably nothing to do (other than enjoy the resort) once there. Another option is to take the direct train to Kyoto and stay at the Westin there. Kyoto is by far the highlight of most people’s visit to Japan. There is much to see and do there.