I'm doing the same thing in our property in Roanoke rapids NC. 240 acres some farmed ,a mix of different size trees and super thick brush in some places.
were using machetes ,loppers , chainsaws , and I bought a Husqvarna brush cutter/clearing saw . Even at this its slow going ,mainly because I'm doing most of it alone , goes much faster with a couple people helping . One cut the big stuff ,someone follow to cut high branches & vines that seem to tie six trees together once you cut them , and another person to get the junk out the trail.
heres a video of what I bought
http://www.youtube.com/watch?v=D2KzJRYbwho