I use a bone saw and cut the pelvic bone and then push the hind legs as far apart as possible. Then I just cut around the anus and pull it all out with the guts. Dont want to cut the stomach open or the intestines. And trust me when I say that you will know when you have cut into the stomach. Makes for a very nasty field dress.

As far as splitting the pelvic bone, I don't think anything works as well as a Zip Saw. I bought one a couple of years ago after watching a guy use one, and I will never go out without mine again. It is a well spent $15.