I know it's an old thread, but thought I'd chime in.
Size and weight have always been an issue for me when backpacking/camping, so my choice in the past has been a Kel-Tec p11 with 12 round magazine +1 spare. That's an amazing number of shots in a small, lightweight package.
Having moved to western Colorado now, I'm looking to try out a Ruger SP-101...more weight and fewer rounds, but I believe I'd be more comfortable (given the local fauna) with some hard-cast .357's.