We are at our place for close to 10 years now. For years I walked... even to the SE Corner that took me an hour and resulted in me being dripping wet when i got there and often unable to sit as long because when sweat turns cold, it is miserable.
The last two years I have started driving 3/4 of the way. I probably walk the last 200 yards. My rationale. My pops scores almost every year. The last 3 he has the 3 biggest in camp. He is struggling and so he goes to the closest blind. It is 50 yards from the bunk house. He doesn't care about wind. He makes a racket. Clears his throat on his walk. Sometimes i will hear the door on the blind slam open when he pees. Is it luck for him? Maybe it is? And if so, then luck helps. Or, maybe location is just good for him! For him as long as he is quiet when the decide to come through he is fine.
If you jump them on the way in.... then you lose. But that happens walking or riding. Once in position... I think that sound/smell dissipates quickly.
Walking is not a loud (and less smell) but it is slow and for those that do hear you, because of the slow pace they tend to react more. The quad has a steady sound moves quicker. Because of that I find the deer on my property freeze and see if that steady movement becomes a threat... when it doesn't (quickly - quad moves quicker) they go back to their thing.
Of course, I am in full agreement with all posts. I hunt in thumb of michigan. They hear quads, side by sides and tractors every single day. If you were in the mountains of CO or Wyoming and it was a new sound. I would never do it.