Cape Royal is a must destination for sunrise/sunset.
In your planned visit to the Grand Canyon North Rim, I suggest making this stop. It is the last destination you can drive too in the park and the furthest from the visitor center. The road (Cape Royal Road) to get here is windy and full of fun turns. If you have motion sickness I might reconsider going here unless your driving. You could ride a bike out to it if you dare, but it is a tight road.
The walk out to Cape Royal is short, simple, sweet and worth your time. It is a short 1/2 mile trail that is flat and takes you directly to a viewing area. There are a few other lookout points along the trail that you can take advantage of, so if you have the time and are not rushing to get to a good sunset spot, do some exploring.
This image was taken a bit off the paved trail. Not sure if that is allowed or not, but none the less it was a great image. If you want to purchase the image you can go to my market place to purchase it Here: http://mkt.com/nathan-st-andre-photography/cape-royal-north-rime