Gunmart, I've hunted elk with an outfitter in Wyoming, in mid October. First, it can get very cold at that time, so make sure you have a GOOD sleeping bag, rated to at least minus 10 degrees, lower if possible. Layer your long underwear, wool shirts, wool pants, jacket, socks, gloves or mittens, etc. A good, warm cap with ear flaps is best in my opinion, although some people like hats, etc. By layering, if it's too warm, you can put your jacket in your day pack.
Don't forget your toilet kit.
I strongly recommend a top line rain suit, and always have it in your day pack. A "blue bird" morning can turn real serious by evening, and the worst thing is to get wet. I like Helly Hanson, but there are other good ones.
I always carry a three bladed Camillus Stockman pocket knife, and a four inch fixed blade drop point knife on my belt. I always carry a canteen of water in my pack.
Waterproof matches, a Bic lighter, a good compass and a topo map of the area in which I hunt. I carry 25 feet of parachute cord, and a container of Dental Floss. Also, a space blanket. Don't forget toilet paper in a Ziplok bag!! Add some lightweight First Aid stuff: Band Aids, a small bottle of Betadine Skin Cleaner, some sterile 4" guaze pads, a couple of safety pins, and a medium curved upholstery needle.
I carry two Mini-Mag flashlights and a set of fresh batteries and a bulb. One on my belt, the other in my day pack.
I always have some beef jerky, a couple of Snickers, and some raisons, for emergencies. (Your outfitter's cook should have a sandwich for you to take when you leave camp each morning.)
I always carry three rounds in my .338 and ten more in a side pocket of my jacket. Many people take more, and I'm sure some, less. That amount has always worked for me, although I take ten extra rounds in case my rifle's zero has changed on the trip, but they stay in camp. (Luckily, it never has.)
Boots are critical. I take a pair of older Herman Survivors, insulated, leather, and a pair of Sorrel Caribous, with two additional pair of wool inserts. I always take a pair of camp mocassins, as they are more comfortable to wear around camp than boots. Also, if you have to get up in the middle of the night (who doesn't?), the mocassins are a lot easier to slip on than boots. If there's much snow, my "gaiters" really come in handy.
If you sleep on a pillow at home, don't forget to bring it with you. I roll my sleeping bag and pillow in a fitted canvas tarp. I want that protection of my bag. I've seen some real wrecks with horses and mules, and I don't want my sleeping bag getting wet, or torn up.
A small camera is easier to tote than a large one. Take lots of film, and remember to use your flash on the camera for almost all pictures. Most often, people think that the sun will fill in where there are shadows but it won't.
I always take a soft bound book, in case I'm snowed or rained in, or in case I score early and my hunting partner is still out with his guide.
Here's a tip. Take two or three coat hangers. They'll come in handy.
These are things that work for me.I'm sure others will have different suggestions. Have a great trip, and I hope you score that "big six!"
J.B.