I don’t think a 1911 or 4” .357 mag are the best choices for your needs. I know when I backpack I like to limit the weight I’m carrying, and both of those are heavy guns. I’m happy with using a .38 special j-frame when backpacking and fishing, but here in Ohio I only have to worry about people. In the several times I’ve backpacked and fished the Smoky Mountains in Tenn and N. Carolina I’ve only see bears while driving, and you really don’t hear about too many black bear attacks. I have taken a Glock 23 backpacking in N. Carolina once and while I found it a little heavy for my tastes, I’d suggest something like that before a 1911 or steel framed 4” .357. Your chances or having issues with any wild animal is pretty rare, and most people that make the effort to go backpacking are pretty decent. I’d vote a small 9mm, a .38sp revolver, or an LCR in either .357mag or .327 mag for pretty much any 2 or 4 legged critter in the eastern US.