Based on John S. Gray’s tables in Custer’s Last Campaign: Mitch Boyer and the Little Bighorn Reconstructed unless noted otherwise. Several people commented on this timeline when it was originally published on LittleBighorn.info; those comments are in italics.
June 26, 1876
12:04: The horse herders passed Rosebud (Busby) “at midnight.”
4:00: The rear guard passed Lame Deer Creek “at daylight.”
4:19: The horse herders arrived at Lame Deer Creek “at daylight” and camped.
5:15: The rear guard arrived at the mouth of the Rosebud “in evening” and camped. 8:00: The horse herders left their camp “at sundown.”
June 27, 1876
5:30: The rear guard camped for the night at the Tongue River.
7:05: The horse herders camped for the night just short of the Tongue River.
June 28, 1876