Personally I don't believe that any noise that the deer hear on a regular basis does any harm. I also believe that a person sneaking to their deer stand would alarm more deer than a 4 wheeler which is ridden pretty often. Although I'm like you and prefer to walk at least 500 yards to my stand, its just a preference. One stand I hunt this year is right next to a grass road in which another hunter in my club uses to drive his truck to get to his stand. At 1st I wasn't to thrilled about it until I started to think that the deer will get used to this and it will not bother them. 1 morning this year while in my stand waiting for sunrise the other hunter drove in about 15 minutes before daylight. Right at daylight I had 3 deer already feeding on my oats. If they were there when he passes it would have been about 40 yards from where they were. I am also begining to believe that when I put out corn, which is when I use my 4 wheeler, is when I usually see the most deer sign. It seems like they have come to understand when they hear that bike, it soon will be feedin time.