We hunt unit 67 Colorado. I can agree with alot of what's been posted. Road access in 67 is everywhere. Still, the elk in first rifle don't see to mind it. Our party has killed 5 bulls in there in 2 seasons. Rag horns yes,but bulls none the less. The last one was well past his prime. Huge old sucker. Half again bigger than the other 2 we killed that trip. So, bulls young and old alike will hold near campsites. At least early in the seasons. You can't just walk up and club them on the head mind you. They can however be killed within sight of forestry roads.
Keeping a low impact approach is key. Someone mentioned "Sneaky". I agree wholeheartedly. It's very hard to do,but you have to be aware of the wind. In our unit,they may not blow out into the next county,but they won't shake hands with you. Especially if your sent gets there before you do.
Case in point. We worked a herd bull one AM. He had a small harem of 6 or 7 cows. One satellite bull in tow. We had him responding to calling with grunts and chuckles. He screamed at us a couple times just to get the hair on your neck all fired up. We put a bunch of pressure on him to no avail. We decided to back out and come back in the evening for another try. We split up into 2 groups. My self and my b-in-law went down to the edge of a park we started him in that morning. The other 3 from camp went around the back side of the ridge he was working toward when we parted ways earlier in the day. Here is where we made our mistake.
My brother in law and I had a destination in mind. We were going to stake out along the lower edge of the park,and watch up the ridge while doing a little cow calling. Simple enough. Except we weren't "Hunting" our way in. We just walked up to the clearing with no regard for the wind at our backs. Well,you can guess what happened. We hit the clearing and the old boy,harem and all,went busting up across the park. I managed to get on him and might have taken the shot except for the cow directly behind him. At less the 70 yards I didn't want to send a 180gr Partition his way out of old Cruncher the 300 Ultra and risk hitting the cow behind him. We never got on that bull again that trip. He was by far the nicest bull we've seen in that country yet.
Had we been paying attention to details instead of making time,we might have killed that bull. You can't cheat that nose. Hunt smart. Low impact and sneaky.