There is a boardwalk in Duck, North Carolina on the sound side. It's a perfect place to watch the sunset. It's a long walk from end to end, through nature, shops, and restaurants. It's a relaxing walk--nothing too strenuous. But you can enjoy the beautiful scenery of the sound side.
There's a lot you can do around Duck, but I recommend heading to the boardwalk to walk it at least once. Maybe every evening around sunset. I usually go there multiple times a visit--not just at sunset, but during the day. If you want a more casual walk, this is perfect.