You have hundreds of wooden posts to install. You will soon learn if the auger or a pounder is the way to go. This will NOT be a small project.
I installed a four wire - barbed wire fence around my 80 acres. It is one and a half miles of fencing. Some 665 T-145 steel posts. All driven in with a manual pounder. Up the hill - down over the cliff and into a valley - around many meadows - - it WAS NOT all flat, level ground. It took me the better part of a year - working every evening. Fortunately my 80 acres is a pure rectangle - 1320 x 2640.
That was in 1982 and it is still standing - straight, tight and true. I check it twice a year and do any required maintenance.
Good luck ...............