350 miles + A really nice full days ride if you stop to sight see and eat along the way.

A great ride to just ride and enjoy all the Black Hills has to offer from top to bottom. 
Sturgis → Spearfish → Belle Fourche → Aladdin → Hulett
Devils Tower → Sundance → Inyan Kara → Newcastle
Edgemont → Hot Springs → Wind Cave
Pringle → Custer → Crazy Horse → Custer State Park
Keystone → Mt Rushmore → Hill City → Deadwood