Start with the hind legs. You should have it started already, so just grab the hide with one hand and pull downward, using the knife to free the hide where necessary. Do both legs until you get to the rump.
Once you have reached the rump, grab the tail and cut along the underside of the tail where it meets the rump, cutting through the bone but not all the way through the tail. Pull the tail downward and the skin from the rump should start pulling away. Once you have the hide pulled off the rump and the leg hide and rump hide are now one big piece, use both hands and pull down toward the neck. Most of the hide will come free. You may have to do a little knife work along the abdomen where the field dressing cut is.
The shoulder area is probably the trickiest. You will have to just work patiently, pulling the hide with one hand and cutting with the other. Pull the hide inside out over the leg, freeing with the knife as you go along. Repeat on other from leg. Pull the remaining hide off the neck.
Remove the head
If you plan on using the neck as a whole roast you need to remove the head. If you plan on trimming as much meat as possible from the neck for ground venison, then this is unnecessary.
Working a knife through all the meat and soft tissue, run a cut through the neck as close to the skull as possible. Once you have reached bone you can remove the head one of three ways: Use the loppers to cut through the neck bone (my preference) Use a bone saw to saw through the neck bone Cut into the joint as much as possible with a knife, then twist the neck around until it breaks. You can then cut the ligaments off the joint and it will fall free.