There are campsites available in all eight of the CGs during the time we'll be there - any opinions on which ones are best, or worst? We like to have shade when possible.
We were happy with Stockade Lake South. Decent amount of shade. Based on almost everyone posting positive experiences of a different campground, I don't think you can go wrong with any of them. I do know that S.L.S. is designed mainly for smaller campers and if your rolling in with a 25'+, then you will be getting one of the sites that has more direct sunlight exposure.
Courage is the feeling you have right before you fully understand the situation
We've been twice, and both times Blue Bell campground caught our eye as being interesting. The covered wagon tours for the Wildlife Loop seem to leave from there and it just has a vibe. On our third visit, that's where we'll be!
If you are talking about Custer State Park only can not help. However a few years back we stayed outside of the city of Custer in a great campground. I believe its worth checking out Ft. Welikit https://www.blackhillsrv.com/
I just can't imagine anyplace being bad at Custer. That is one place I'd love to just move to, we had so much fun exploring the area, eating at the small mom and pop restaurants in town and even ducking the hail storms that seemed to happen often in summer. Grandkids got to see their first buffalo up close and personal and enjoyed swimming in the lake also.