OK, so I'm ex-Army. I get where you're coming from, trust me. Up until two years ago my pack still weighed 50lbs.
It's been going down steadily, with the use of more modern, lightweight options.
I wanted to agree with the thought someone had of a Kindle, or a Nook to replace your books. Load it up with reading material, charge up when you're in civilization.
Compromise on the hatchet...go with a small machete if you just HAVE to HAVE a large cutting implement. There's a small Gator machete by Gerber that's pretty cheap, and a lot lighter weight than a hatchet. Doubles as a saw and chopping tool, as well as a hole digger if needed. Use a rock or a tree limb if you need a hammer.
I don’t see any wet-weather gear.
Ditch the dry bags for a couple of 3 mil, 55gal trash bags. They can double as a ground cloth, dry bag, emergency rain gear, etc…much more multi-use and lighter weight option.
The flint (Ferrocerium?) is fine…a Bic is better. A Bic in your pocket and one in your bag is best.
Welcome and thanks from another old dog.
Somewhere in this train of info you asked about how to mail stuff to yourself. Two planning books for the AT have all the info you need -1) AT Workbook for Planning Thru-Hikes and 2)AT Thru-hike Planner. Both have the Post Office locations for all trail towns and planning sheets you can copy and use for about anything you need to figure out, including all the mileage information, both north and south. Then there are other trail data books that are more useful on the trail as they much more compact. You can cut out the sections you need, stick them in a ziplock bag (freezer style) and they fit in the belt pockets of the Catalyst. Mail ahead the next batch.
+1 on those folks who said do some short shakedown hikes, a few days at most to figure out what works for you. You will find out as others have stated, lots of stuff you start out with when getting into this "pleasureable" experience are not needed.
Professional Prevaricator: Part-time dealer in Yarns, Tales, Half-Truths, & Outright Lies -1st half-hour session at no cost (Lawyers and Doctors excepted).
I was considering a mat or pad or underquilt -not so much an all-three consideration but a one over the others. FireInMyBones has given me some advice on the quilts offline. They are a little more expensive but the weight and size is a major desire.
My 2 cents.
For wet weather I use DriDucks. They are very lightweight, pack down small, and are affordable. They are good as windbreakers as well. The one drawback for me is that they tend to be a bit fragile - not recommended for bushwhacking.
If you go with these, be advised that they tend to size big, so if you wear a x-large you might try a large... I like them loose, because I can layer them over thick fleece, but if you like a tighter fit, try them on in the store first. I've seen them at most major sporting goods stores.
here is a link to their online site so you can see what they look like.
In the Marines, we normally had a list of "madatory" items in the load-out.
In the real world, longer distance camping with your own gear is so much better than going to the field with all your mandatory junk in the pack.
What I teach our Scouts is:
Take what you need, and need what you take.
I'd suggest that you do a few camping trips yourself with all your gear and see what you don't use.
Some people spend an entire lifetime wondering if they made a difference in the world. But, the Marines don't have that problem.
Ronald Reagan, President of the United States