If the load is being held back by the cable and the cable long enough you could always let gravity do its job by doubling it back to the bottom and attaching it to your tractor and then you drive up letting gravity take the load down. Naturally you need a pully or a tree for which to to double the cable around.
Another method could be to attach an old wheel to your tractor draw bar (bolted so as it does not turn) and if the load is within reason 2 or three wraps around the wheel being held using gloves you could just let it slip its way down.
It is amazing how much of a load a pair of hands can hold back with that kind of friction a few wraps can provide.
If a tree were handy, about 3 turns would act as a super brake.
I once rolled a 1000 lb steel H-beam into place by simply wrapping 3 turns around a trailer hitch and just eased off rope as needed.
We used steel rollers on a 'trail' of overlapping sheets of plywood and a couple of guys would replace the rollers as the beam moved ahead.
Had no problem whatsoever holding the beam in check at all times.
The rope was 3/4 poly, the run about 300ft with about a 20 ft drop.
The rope brake worked like a charm and we were able to position the H-beam within inches of its resting place.
Helpers would, as the beam moved foreward, simply use levers (crow bars) to steer the beam into position as required.
Stopped you could not move it, but in motion you could lever it any which way.
While a crane would have been the correct method, the monster crane we would have needed (1000 lbs @ 300ft) would never have been even able to get one on site.
Be careful!