The Rosebud Battlefield is about 30 miles Southeast of LBH by road. Not sure was is there now, as I haven't been there since about 1988. Most of the battlefield is a Montana State Park, with some on private land. There are several great books on the subject: "Battle of the Rosebud: Prelude to Little Big Horn" by Neil Mangum is available on Amazon. It locates the various points on the battlefield better than Vaughn's 'With Crook at the Rosebud", but the latter is a great narrative of the battle. Google the Battle of the Rosebud and you will see numerous references. Crook claimed he won the battle because his forces held the battlefield. Strategically, it was a bad defeat, as he withdrew to his base at Camp Cloud Peak (where Sheridan, WY, now stands). One can question if this lead directly to the LBH battle, which happened a week later. The whole concept of the Big Horn and Yellowstone Expedition of 1876, trapping the Indians between three columns, Crook's the main column, Terry's, with Custer as his strike force commander, and Gibbon's column, which joined with Terry, was lack of communications between the columns. Crook and Terry had no idea where each other were, nor what action they might be encountering. Couriers could not get through from Crook to Terry or visa versa, there were just too many Indians around. Radios or aerial recon would have been the thing, but of course they didn't exist then.
Have fun out there!