First off, if you want to go for ten days, and you think you can make it for ten days, GO FOR IT. Almost every hunt I go out on plans to be a 10 day or sometimes 14 day hunt. Sometimes I tag out and it doesn't last that long, sometimes I move areas early, sometimes I stick it out the whole time. However, if you carry 10 days of gear in, then you at least have the option of either coming out halfway or staying if the hunting is good. Nothing is worth than being in good hunting and having to head back for the truck, especially if your hunt isn't even over.
Secondly, you wont need to carry 75+ lbs on your way in. Go in moderately light. For me, 10 days worth of gear and food comes in at around 29 lbs without water. I have fine tuned my gear a bit but there is no reason you couldn't go ten days with a weight of say 45-50 lbs.
As far as elevation sickness goes, I don't know what to tell you per say. It seems like some people get it and some dont. I hunt high every year and I live in Portland Oregon at less than 250 ft of elevation. Breaking into high elevations has never been a problem for me. You can feel the difference for sure, but altitude sickness has never been an issue.
The guy who mentioned taking a trip to test your gear out on a two or three day backpacking trip somewhere closer to you is spot on. That is probably the single best piece of advice on here in terms of preparing for your hunt.
Lastly, if it was me. I would scrap the idea of hiking in one mile and testing the waters by camping there. You can hike a mile in 15-20 minutes on a trail. Unless you want the illusion of a backcountry camp that bad, why would you not just camp at the truck?! one mile each way per day is not enough to make it worth being away from the truck. You would be much better off eating better food, getting better rest, and hiking a little more each day. For me the tradeoff comes in at around 4 miles. IF you camp 4 miles in then the tradeoff of saving 8 miles on your legs per day is worth it over what you lose. Anything before that is hard for me to justify packing to.
Backcountry hunting has been made into a glamorous occasion by many outdoor media outlets, but really, is it any less real to kill a buck on foot 3 miles deep while camping at the truck than it is to kill one two miles further up the trail and be sleeping somewhere else? A hunt is still a hunt, and if you are getting to hunt in the mountains I have a feeling that you will look back and enjoy the experience either way.
Kevin Underwood- http://kunderwoodblog.wordpress.com/
Bitterroot Bulls has some of the best advice I've read in years! Don't push too hard, match enthusiasm levels, don't bite off more than you can chew. These are things to really take to heart. And test your stuff beforehand, in real conditions, not just in the back yard. Set realistic goals with progress toward said goals measured by realistic objectives. Using the books in the Eastman library is the absolutely BEST first stage anyone can do, and while you're rereading them, learn as much about your chosen area as you can without putting boots on the ground. Get together and test your food as well. Eating cardboard isn't about to make you want to eat more of it, and you have plenty of time to flesh out some nice backpacking meals. You're working in the right mindset if you take this as an adventure! Some small niceties make it really great! If the country's not tinder-dry, I'll pack in some cigars and a little nice cognac for an after dinner treat. And hike your butt off in your boots before you set foot in the back country. Blisters and foot issues aren't welcome in any camp! With the advice you're getting, the research and early planning you're doing, I'll bet you guys will have the time of your lives!! But remember, the drawback to all this is that you'll find you REALLY want to go back, again & again!! Oops: too late!! You're hooked! Welcome to the high & wild!