ROTFLMAO! A chain saw huh? If your gonna use a saw, a sawzall works.
Deer here are like rats, there are so many of them it is a waste of time to really worry about every little scrap of meat. First, if your hunting for a "trophy" and have dreams about Boone and Crockett I worry about you to start with! That has nothing to do with meat hunting and feeding yourself. The last thing you want to eat is an old buck! Chronic wasting disease and the deer version of "mad cow" is far more likely in that old buck. I never want anything past a 4 point or a 2 year old doe. Bambi suits me just fine
At a kill, or if a deer is brought to me by one of these hunters that don't want to clean it, I lay it on its belly with the legs out to the side and make a cut accross the tail about 6 inches or so and take a sharp knife and cut under the skin on each side to the back to the head. Then I take a beaver skinning knife and peal the back area of the hide and then cut out the backstrap all the way to the head. I then cut out the shoulders and hams to the joint, front and back, and pop the legs out at the ball joint and remove the legs, skin and all. The rest is left or hauled to the ditch. All I am missing is a little neck meat and the tenderloin. I do not open the body cavity.
When I get home I can quickly skin out the legs and cut off the feet and wash it down, clean off the hair and pop it all in the refrigerator to age. I do not even think about gutting and skinning as I would a beef calf. Any of the deer processing places will either give you all the deer hides you can haul or sell them to you for 50 cents to a dollar. I will not be caught skinning a deer for a 50 cent pelt
As to germs, pleeeeese! Ever been to a feed lot and a slaughter house? They stand 'em in manure for weeks until they are covered and coated in feces. Then they kill them, hose them down with a little water and take a big saw and cut them in half! I am sure that blade does not carry that residual feces throughout the meat. That is why you never hear of a salmanilla outbreak