tpstall, I was in your neck of the woods last weekend. About 20 miles north of Bracketville.
I as usual will give you different advice than most others. I think you need 4wd. Exspecially for the cedar. With 4wd you can put your bucket at the base of the cedar. Lift and drive forward at the same time. With 4wd the front end loads up and gets all kinds of traction. With 2wd the rear tires unload and you just spin. I would rather have a 4wd 4500 than a 2wd 5500. One you have a cedar root ball flipped out of the ground ready to be pushed in a pile. The other you will have to hook on a chain, pull it out, remove the chain, then push it into the pile.
If you get the 2wd and find it too slow, rent a dozer and be done with the cedar.
For caleche work, either will do fine. If the caleche is already in place I would use a angle blade to pull it back to the center of the road like a motor grader does.