I bought all my material from 84 Lumber in Lancaster, Anytime I set posts in the ground I've always used concrete, never had an issue, soil can erode as can gravel concrete isn't going anywhere. Not saying I'm right or wrong but how I've always done it. It took me about 2 days to set my posts (over 90 of them), stretching the fence didn't take long, I had 200' rolls and used a fence puller (a must). It was just myself and my FIL and my 3 y/o son . All in all I had to take breaks cause of rain and it being too wet to do anything. but I had it up in a week if I count the days I was actually able to work on it.