Colorado is one of those states where EVERYONE goes to. Its a yearly party for a lot of them, and a four wheeler week of racing around the mountains for others. I went once and was shocked at how many people there where on the public land, how many ATV's there where, and at the lack of animals. Fortunately I went with a couple of guys who had been before and we where with an outfitter that packed us into the Wilderness area far enough away from the National Forest to be able to find animals. Two out of four of us shot 5x5 bulls. The other wasn't in good enough shape to get to a raghorn that was out sunning himself, and the other wouldn't get out of bed until daylight.
When we got into Steamboat Springs, everyone who saw our little 5x5 bulls was amazed that elk that big where still in the mountains. It was so bad that I've never had the desire to go back there again. Idaho can be just as bad if you are near public land that allows ATV's.
If you go, be sure that you are away from everyone else. Private land is well worth the cost, but paying for a packer to get your well into a Wilderness Area is the only other option I would consider.
Much of the state is that way, but with a little homework and leg work, you can find good places to hunt without packing ten miles into wilderness. I'm not a great elk hunter, but I always get into elk less than 2 miles from any roads, on national forest, and I see plenty of nice 6 points at camps and in the backs of pickups. It's a challenge, but I feel it's well worth it. There's still plenty of good hunting to be had.