Eden is not far from me, 3 hours, been there many times. Small town, uphill from dock., about a 1 mile walk. No local buses from dock to town. Ships run the shuttles like you said. In town, couple of supermarkets, pharmacy, liquor store, pub, banks, etc.
A Welcome Centre dockside (pictured)and a few market stalls selling handicrafts etc on cruise ship days. Meeters and greeters will be there, suggesting things to do. I doubt if there will be independent tour operators there, but there might be. Whale watch tours also go from that area. They are good. Is NCL offering shorex? Might be a good idea for you to see around the area.