why dont you spend a day or two finding all the sets, then get all the holes clear with a petty strimmer, axe, machete or anything else that will do the job then leave it a couple of days the go back and ferret. if you have enough nets net up all the warrens then go back to the car leave for a hour then go back as silently as you can and ferret all the warrens.
the advantage of netting all the holes is that if one slipps the net it will be back netted in the next warren.
when you have finished fill in all the holes then leave a week then go back and see witch sets are still been used.