Just a couple of additional weight saving tips from an experienced backpacker:
A bandana weighs less than a towel or washcloth, and takes up less space too.
Don't cut out all of your extra clothes. Even if you plan on wearing the same stuff (yuck) for three days, you really should have a spare set in a ziplock (to keep it dry).
Not sure what sort of knife or multi-tool you have in mind, but my usual backpacking knife is an AG Russell Hunters Scalpel that weighs 0.8 oz.
Water filters are much heavier and bulkier than iodine. Just sayin'. I know some folks can't stand the taste.
The bear bag "rope" can be very lightweight - just some nylon clothesline cord would be more than sufficient.
Pick one light, the smallest and most convenient for you. Bring an extra bulb for it, and maybe extra batteries (I rarely ever use a light when camping, so am confident that one new set of batteries is enough).
Research the trail or area where you'll be hiking, and talk to people who have been there recently. Find out the current water availability. You may need to carry a lot less (or a lot more) than you think.
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The heaviest pack I ever hauled was 65lbs. That was a week-long early spring backpacking trip in the Ozarks, with anticipated rain and freezing temps. Tent, winter-weight clothes, wool blanket, and cook stove were the primary contributors to the weight, but necessary. Not to mention I had 11lbs of food for the week.
For an overnight or 3-day trip, I'm usually between 25 and 35 lbs.
With the 65 lb pack, I really had a rough first day - only made 4 miles. But after a couple of days my pack and strength picked up and I was back into a more reasonable 15-17 miles per day.
I figure these speeds:
Bushwhacking with a full pack, 1 mph.
Lightweight daypack on trail, 4 mph.
Heavier pack, mixed bushwhacking/trail, or other unusual conditions could put me anywhere between.
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Summer days are long, over 14 hours of daylight. So even at only 2 mph, there's no reason why an average hiker couldn't make 25-30 miles per day. But as fall approaches, the days will get much shorter. Plan accordingly.
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I used to carry spices and seasonings in old film canisters... until someone explained all of the toxic chemicals used in manufacturing film.
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One more common sense tip: eat the heavy food first.
