Getting in shape is a good thing and will help all aspects of any type hunting.Your body just has to adjust to altitude by being there and it just takes time.It's a blood thing.it shouldn't be much problem till you get over 6000'.In a perfect world,it would be ideal to spend a few days at high elevation before you actually hunted,if not,take it slow and gradual and just listen to your body.
Not only do your boots need to be broken in but your feet need to be conditioned to them as well.Spend the last month or so before,wearing those boots a lot,exercising,shopping,working,whatever.Get your feet used to them.If your feet give out or get badly blistered,your hunt is over.It may be worth your while to get quality insoles for your boots.Everyone's feet are different.Some feet need no support,some need a lot of arch support or heel stabilization.
I agree about Cameron's book.He is a sadist and you don't have to hunt exactly like he does but someone who spends so much time living in that country can give you a lot of real advice about clothing,water treatment,hydration,navigation,safety etc..It contains a wealth of information from someone who knows.
A GPS is good but I would back it up with a map and compass.
Above all,lose the eastern hunting mindset.I grew up in the East and it took me awhile to adjust to hunting in the West.Where I grew up,there were deer on every square mile of land.In the West,there may be miles of country with no game at all.They may have been here yesterday but are miles away today,so don't be too sedintary.
You just have to keep moving till you are into game.Either sight the game,find fresh tracks,hear elk bugling etc or keep going till you have located game.When you are sure you are in good country,nothing wrong with sitting and glassing for a few hours.Nothing wrong with sitting on waterholes or wallows either if the are hot,right now.Just make sure you are sitting where game is now,otherwise,keep moving.
Game may not be as visible as you expect them to be.Learn to pick the landscape apart with your glasses.Just because the image of a deer or elk doesn't jump out at you,doesn't mean it isn't there.Try to pick out the tips of antlers of a deer bedded in the shade,an ear,the cream color of a mule deer's rump,the color of an elk etc..
If it has been very dry and water sources are few,animals will be more concentrated and easier to find and hunt.When we have a real wet season and everything is very green,animals are scattered everywhere and are much harder to hunt.
Remember,in the mountains,you have a prevailing wing but you also have thermals.In the mornings,the cool air will be drifting downhill.After the sun comes up over the mountains and the temperature starts to rise,that down draft starts to reverse itself and the thermals rise up the mountain untill late evening when the sun drops behind the ridge again and the thermals will draft downhill again.
That is why animals often feed low during the night and head uphill toward their bedding grounds at daylight.They are traveling uphill and the cool air is drafting right downhill into their noses.It is hard or impossible to sit and wait above them during these downward thermals.It may be possible to sidehill toward them or better,put them to bed and plan a stalk when everything is right.
If you make a long,looping stalk on a distant bedded animal,keep in mind that everything may look different once you get over there,especially if you come in from the opposite direction.I used to sometimes draw a little sketch of the spot where the deer was bedded,showing all the prominent landmarks and as I approached from the opposite way,I could turn the sketch to match my approach and it would guide me in.
Nowadays,it would be a simple matter of taking a picture of the hill side the deer is laying on and refer back to that image to guide you in.And always be aware that bedded animals frequently get up,stretch and bed down a few feet or yards from their initial bed.As you approach,be ready for this and don't just focus on that original bed unless you can visually confirm he is in it.He may be bedded a few yards away and peg you.
Dwight Schugh also has an excellent book on bowhunting mule deer.