One other viable option is : Since you are hunting on public land, I would assume that your stand is not perminant. You would most likely be in a climber. So take the climber and move closer in to the area from which the deer are coming. They may not get to you until almost last light, but what is keeping you from going to them? If you move further up their trail, then it will be earlier , the next time they come by. If it is still not enough, note where they are when you first see them, and move even further up their trail. Keep working your way back until you can get a shot opportunity with decent light.