Good advice on the boots and changing weather. 100% agree. As I've mentioned in a couple other threads recently...do some extra reading with places like this:
http://cpw.state.co.us/learn/Pages/EHU.aspx
Tips/advice can take pages, especially for someone who hasn't hunted out West. Hopefully outfitter is steering you toward places to find elk, so that should help. Just be sure you are fit, have good personal gear, and are ready/able to shoot past 200-300 yards if required (it is very common to need to out West, since it is big open country).
Muck boots etc would be a disaster out here. In most cases, you'd hike around (a lot of up and down) for a few hours and your feet would be blistered and you'd be out of commission. Cheap boots will usually not give good support (or too much), not fit well, not keep you dry or some other combination. As others have said, invest in a well-made pair that fit well and that your feet don't slip at all in. Probably safe to get a lightly insulated pair for all-around use. Ideally, a person would have a lighter-weight, non-insulated boot for warm days with lots of hiking, a mid-weight insulated pair for a lot of the fall, and then a heavy insulated winter hiking boot (if hiking a lot) or a good pair of Pac boots, if not walking a lot and sitting a meadow, trying to keep feet warm. If I were you, third season, I'd get a good pair of mid-insulated hiking boots that you'll probably have to spend $200-$400 on and use them 90% of the time, but also maybe have a pair of dedicated, cold-weather boots, that even if they aren't great for hiking, you could wear and stick some foot warmers in, in case you end up sitting a meadow for hours. The goal is to stay warm and dry.
Clothes - no jeans or cotton. Find something that breathes and wicks moisture. Wool or some synthetic (something like smart wool is much better than some cotton t-shirt, that will get soaked with sweat and freeze you to death). Make sure you have layers that you can add and remove. You don't want the great big, insulated coveralls as your main source of clothing - unless you aren't going to walk far and just plop down on a meadow 200 yards from the road. Otherwise, you'll sweat to death walking and they'll rub and chaff. The tricky part is that usually when it's cold, you have to hike and spent a lot of energy getting where you want to go, and then if you get somewhere to sit, you need to stay warm (two completely different clothing requirements). So, stick the clothes/layers you'll need in a pack, head off in way less clothes than you think you'll need (it will seem crazy, but you'll be sweating soon enough) and then when you get where you plan to sit and watch you won't be completely soaked with sweat and you can start putting your warm layers on. Even if hiking all day and not sitting, good to have warm clothes along (and some basic survival stuff), in case you get stuck out for the night. That's a start at least. As others said, bug the outfitter too, it's there job and they should have a list of stuff and also tell you how much hiking vs sitting etc you'll probably be doing (but some of that will probably be up to you too).
