Fireplug - great to hear you are giving it another try! While I have never hiked more than 215 miles in a stretch on the A.T., I do have "foot and Achilles Tendon issues," so here is my input on what has helped me:

Shoes: Trail Runners (recommended by my sports med Dr). - BUT REPLACE the inserts with PURPLE SMARTFEET (recommended by my Physical therapist). LONGEVITY: Trail runners - only wear for 300-400 miles on the trail. How to know? Look at the soles - look for "crinckles/wrinkles in the side of the sole. If visible, they need to be replaced. My experience: 300-400 miles on the A.T.... )

Stretching: Don't neglect this!!!!

I will be on the trail starting at Clingsman in June, so I am sure we will not meet; however, I wish you the best!!!