There are comments in various reports andnotes of the march, which puts the scout at approximately the locale of Lame Deer to about Jimtown. The heart of modern day Cheyenne territory. % miles further is the Muddy and 10 miles beyond there is Busby. So Reno progressed to within a half days march of the regiments halt on the evening of the 24th.
The point about Reno's scout which is continually missed and passed over is that on his march of the 10th June, having just begun the scout, he passed over (across) the trail of the camp move from the Tongue to the Rosebud and then caught up with the trail again when he deviated from his orders. Bradley with Gibbon, also discovered this movement and that whole phase of events cost the expedition nine days. There were some odd decisions by all the senior people. Gibbon, Terry, et al. Reno certainly missed the trail of the camp move and the only excuse is as Lord noted, that it rained hard and Montana rain is quite hard.
Terry had an interest in the Tongue river because of previous Indian fighting expeditions into that area in 1865 (Connor) and the marches of recon which had travelled the Tulloch to the Tongue via Lame Deer.
There is a brigade of thought that Custer should have done what Terry suggested and followed the Rosebud rather than turning for LBH. All that would have happened was a repeat of Crook's drubbing and probably on the same terrain. Custer understood from 1873 that if he did not strike first, then he would be attacked. He understood that without a shadow of a doubt. This was stated by Sheridan. Once discovered there was nothing to do but strike urgently. The regiment was discovered and whether they marched as they did or followed Terry's wishes to continue the Rosebud, they were discovered. Not only were there camps to Custer's front - there was one following along behind. If they had camped at Busby and marched along the Rosebud on the 25th, the day's march (30 + miles) would have put them on the Terrain of Crook's battle - with Sitting Bull alerted to the presence and an exact repeat of the all night march by hostiles to hit 7th Cavalry marching on 26th June.