If it was a Fedex TPS load I wouldn!t even consider deadhead,If it was a Conventional non discounted load I would go about 30% or 150 miles,,but you have to think of the deadhead at the end. If the load drops in the middle of now where and you have a 200 mile deadhead to get to a decent location for your next trip,thats a big consideration.. Most years I average about 33-35 % deadhead..