Are you looking for quality or quantity?
Most of the whitetails in Western SD are along the major rivers - Missouri, Cheyenne, White, etc. They can also be found near most agricultural areas, but then you are dealing with private land.
Go to the SD GFP website and look at the sportsmans atlas for public lands. You can also get draw odds for each unit. I am assuming that you are looking for a rifle hunt since you are looking for a specific unit. An archery tag would allow you to hunt the entire state.
Send me a PM if you want more specific info. I would be glad to provide additional help. I don't want to share too much specific info on an open forum.
Brian