I have just seen this post. I have done over 1000 miles on the Appalachian trail. I did it in three sections a few years apart but include both termini of the trail in Maine and Georgia with a large chunk in the middle; visiting seven of the thirteen States involved. It is a very sociable trail and many interesting people and wildlife are met.
I do hope to go back to complete some of the gaps I have- first probably Daleville, VA to Harpers Ferry, WV. I have done Harpers Ferry to Boiling Springs, PA deep in the Civil War area; one time sitting by a creek for lunch if Union or Confederate troops had trotted by I would have believed it. The countryside was so familiar from the odd film I have seen on the war.
Apart from the flights to get there it can be an economical trip as you have only food to find. Visiting trail towns is a must to get the atmosphere, resupply, have a decent meal or two and hostel for a shower. A thru hike is estimated at $2+ a mile but as the trail is over 2000 miles long about $5000 may be required. However some do it on less-it does depend on how many towns you visit and how long you stay there. Sometimes I went into town arriving in the afternoon; resupplied, did laundry, had a big meal, stayed the night then left after a big breakfast. I recall eating a five egg omelette ! - you do get a hiker appetite after many miles. Trail town visits/resupply were usually five days apart so not too much food weight is added to your pack.