The rest area at the SD/MN boarder has been rebuilt. It has been under construction for a couple years and the new facility looks really nice. The building itself isn't open yet nor is the landscaping in. That work will be completed Spring 2020. I will post updates to the cache as work progresses. The parking area is open!
SD is divided north/south by the Missouri River. This half of the state - east of the Missouri River is known as East River. No cowboy hats on this side of the state. This side of the state is home of the 'seed hat'. Buy enough seed in the spring to plant your fields and you will get a free seed hat. Lots of small grain grown on this side of the state. The last glacial age left a numerous pot hole lakes
The cache container is a simple ammo can for now. I will upgrade it and stock it better. I will post updates as that happens.
Enjoy your time in South Dakota.