Some of the earliest backpacking experiences I had were in the Army, and I have to say that I didn't at all miss wearing a steel pot or carrying rifle and ammunition and, and ... plus it's a whole lot nicer to walk on a trail than move tactically through the woods. There aren't many military items I'd be inclined to carry now, but things might have changed I suppose in the 30 years since I got out! :-)

My question is about your aspiration to hike the AT: you live in SoCal, why not the PCT? IMO it's overall a better trail. Clearly if it's the AT stuck in your imagination, do hike it --- it's a great trail too. Just not AS great unless your focus is on the culture/history/geography aspect of the east, or you like the idea of sleeping in shelters or something like that.