Basically everything about even with Denver west is all mtn region. If you can go I would. Its a experience of a lifetime. Even if you don't harvest a elk. Just seeing those mtn's, and hunting them is a worth while life experience. One you'll want to do over, and over. Don't miss out on the chance!! If anything it'll be a break in trip.
If going in Oct. rifle, I'd be prepared for winter weather. You may get snow, and may not. But your going to want to be prepared for it. I usually pack 3 sets clothes. Light weight if warm, mid weight, and heavy. My mid & heavy are waterproof. A good pair hunting boots, water proof, insulated, good traction, and comfortable. I don't suggest rubber boots for Colorado. Bear spray, I wouldn't sweat it. Bears seem more scared of hunters than anything. I've had a few follow my tracks in snow before, but never got close enough for me to even see them.