I've got a friend that through hiked the AT this past spring/summer leaving on March 24th and finishing on July 6th. When he finished he had the fastest hike of the year and from what he said it ended up being one of the fastest hikes of the season.
He kept a journal that documents his preperations and the trip itself very well, this can be seen here:
http://www.trailjournals.com/entry.cfm?id=207796As for gear, his focus was on weight, the day he left his pack weighed around 15 pounds. As for a knife (since this is a knife forum after all...) he didn't have anything big, just the CRKT P.E.C.K. that I had been carrying on my keychain up until the week before he left when he realized that I gave him when he realized that the knife he had was bigger than he wanted.
I highly recommend reading his journal, in addition to being full of information it's a good read.