Bear Butte Lake is located in Bear Butte State Park. This small lake is home to Bullheads, Crappies and Northern Pike. Hiking Bear Butte is probably the most common activity in the park, however there is a small campground and a trailhead for the Centennial Trail.
Bear Butte Lake Campground
This a small campground located on the north side of Bear Butte Lake. There are 
15 campsites (detailed description of each campsite here) and a tent area. The sites are non-electric and are available on a first-come first-served basis. The SD game fish and parks has a campground map here. This is a small, quite campground and has a couple of unique rock structures.
Bear Butte Lake Trailhead
Bear Butte Lake has a trailhead for the Centennial Trail. It is located on the south side of the lake. 
Head north to hike the Bear Butte Summit trail (no pets, horses or bikes on the summit trail) or south about 7 miles to the Fort Meade Trailhead.
This is a great place to enjoy the Black Hills. It is right on the fringe of the forest and is mostly rolling prairie.  This could be a great spot for a day trip. You could be dropped off here, then head the 12 or so miles down to the Alkali Creek Trailhead and get picked up there.
Location
The campground and trailhead are located just across from Bear Butte on Highway 79.
View Enjoy the Black Hills in a larger map
Hi Josh, My husband and I would like to hike the Centennial Trail from Bear Butte to Black Elk in the beginning of September this year. We would like to spend nights in some type of lodging, not a tent. Is that possible? Also we will be driving from St. Paul, do you have a suggestion on what to do with our car? Last year we did the Camino de Santiago-the entire length so not totally inexperienced. Thank you for any help, Cyndi
the El Camino! Excellenta!
For Bear Butte, no. The state park campground is beautiful and primitive.
It is 11.37 usd per day. The trail you wish to travel is 15 miles or so away. There’s also a cost to use it like 20 bucks.
I hope this helps you