RE: .357 magnum
I love the .357 Mag, and I'm a big fan of the Ruger GP-100. It's a bit on the heavy side, but that how I like it. It's built like a tank, the recoil of 158 gr. loads is very manageable, and my groups are better than those of any of my autos.
By the way, I would recommend a 6" barrel. The 4" is great for concealed carry and home use, but I'd want the extra velocity and accuracy of a longer barrel out in the wilderness.