First of NEVER I repeat Never trust your life to some one else like that. Always plan to take care of your self.
What you need is:
small day pack(pick your pack after you pick your gear that way you don't get to big of a bag and fill it up with gear you don't need.
Blanket of some kind and or a small tarp like Visqueen (clear plastic for painters). you just need something to keep the wind and weather of you you and 5X10 is more than enough.
Water purifier, Find at least a water bottle with a built in filter at minimum, a hand pump filter is best.
Fire source, a source if ignition and something to sustain flame. small and simple is best.
Small first aid kit. Nothing you don't know how to use. Keep it simple. Include an anti histamine Advil-Tylenol, and Midol(altitude sickness), and chocolate(altitude sickness)
Survival food, some thing you don't like to eat. That way if you need it you will have it. If it is something you like it is likely to disappear after lunch.
GPS and compass do have them and do you know how to use them? If not learn. If you are going with your brother then look into getting a set or Garmin Rinos. Very good GPS unite combined with a very good two way radio system.
Send for maps of the area, even though you are going with a guide you should still study maps of the area and learn the lay of the land a little bit.
A really good set of boots should be bought first thing in the morning and you should start breaking them in yesterday. Plan on insulated boots and non insulated. Bad boots will ruin your hunt so fast it will make your head spin.
Good luck and have lots of fun.
* (Swinging club) Whack! whack! whack! *
Nope, the old nag's still dead .