To catch a sunset without missing much else.
The Cameron trading post is pretty cool, although a little touristy. Good food and a massive store[s] will keep you occupied if you have time to spare. I'm not sure what the rooms are like as we stayed in the RV park, but enjoyed it as an overnight stop.
When you get to the GC you could explore the viewpoints around the village area and up to Hermits rest to the west. To catch a sunset and not miss too many other viewpoints after dark, [while not having to back track] you would have to make your way along Desert view drive and witness the sunset closer to the east kiosk. Lipan point is a popular choice or you could make your way to the Desert view viewpoint and the Watchtower, which is the last one in the NP. I think the sunset would be around 6.30pm in March and you would be under an hour away from Cameron starting from Desert view.