He'll probably be back. As long as you don't boot him off his bed, I would venture to guess that the atv will have very little permanent impact on him or his movements. About 5 years ago I had a similar situation on my property. I had a stand right on the edge of the property line and an atv (that didn't have permission from the farmer) came roaring by. Screwed up my hunt. Well, this guy would periodically scream around the the fallow field while I was in the stand. I watched this big 10 point on several occasions that bedded down in the fallow field. Just before dark he would pop up and just kind of stand there until dark. The atv would come roaring down the path within 50 yards of this buck. As the atv approached, his head just slowly sank to below the weed line. When it went by, up his head came. I watched this three or four times and the buck never broke from his position and was never spooked. So if there is a moral to this whole thing I guess it would be that you never know what the cotton pickers are going to do!