It's interesting that the Confederate states should have a greater problem with bandits and deserter gangs than the Union. The war was fought largely in the South, but there were wide areas never impacted by combat and campaigning. I was looking for some sort of calculation of how many men in a rural county, e.g., sheriff's posses, patrollers, militia, would be allocated on a routine basis to control slaves. Two? Twenty? Fifty? Do the math and you have a battalion, a regiment, etc.
As for guerrillas, they would target defeat of the enemy power and tie up regular troops or militia. Criminal gangs would be busy surviving and stealing for profit. No matter the nature of the group, this is still a significant public safety problem. In my reading these groups ran around without much interference. I wonder if slave patrollers were much of a match against deserting veterans or serious bandits.