The Pawnee National Grasslands allow shooting of metal or paper targets. Dont be the guy that takes his old TV out there or some exploding target or it is gonna get shut down. Also find a spot with a reasonable hill for a back stop. There are a lot of houses scattered throughout the area so make usre your bullets are finding their way into the earth and not riccocheting all over. There are also lots of places west in the national forrests. Silverthorne has a free 100 yard range with benches and all that is rarely crowded unless its right before hunting season. I have seen people take targets up the hill behind for further range but think it might be frowned upon. Happy shooting!
Try to put your tree stand in a tree with plenty of background cover, keep the prevailing winds for that time of the year to your face, and take care of those pesky squeaks and creaks your stand may have developed while sitting in the shed. A good treestand lube can be made by heating petroleum jelly until it reaches a liquid form. Some hunters have reported success by including a cover scent in this mixture before applying it to their stands.