Unless something has changed and I doubt it with the Annual Sturgis Black Hills Motorcyle Classic in full swing they are open 24/7. I haven't been there for about a year, but Ft. Thompson is a pretty unfriendly joint. I won a hand pay in the middle of the afternoon and took over an hour to get someone to pay me. Never even got offered a glass of water. Same way anytime I have been there. The place was nearly deserted. Go figure. The Lower Brule joint is a ways off the beaten path. I think they have fixed the east road down to it. For years it was 10-20MPH at best. Don't know which way you are coming from but Hwy 34 from the Hwy 45 junction to Ft. Thompson has been redone and isn't quite the suicide trap it was, but watch out for the Walleye Fisherman pulling a camper and a boat at high speeds. Lots are fueled by you know what. I know, I used to be one of them when I lived there. If you are driving I-90, bail off at Reliance, and I would suggest taking the first road you come to for Lower Brule, rather than the second, it is just right after you go by Rattlesnake Butte, it is the big hump with all the towers on it.

Hope this helps.

Mark