PA Plumber
Addicted to ArboristSite
What is the terrain you will be skidding like? If it isn't too hilly or muddy, you can find 2wd farm tractors in the 60-100hp range for relatively cheap. Compact tractors have a much higher retail value than a farm tractor that is too big for most people.
Most of our skidding is done with a 2wd tractor when possible, and gets through some pretty hairy spots.
There are a few fairly steep ridges. About 80% of the timber/pulp is on flat or gently rolling ground.
It could get muddy, but I try not to work in the woods when it's real soggy.