For outdoor use like you propose, I too would pick the Ruger. Stainless, of course, will rust if neglected just as blued carbon steel. However, the nice thing with the Ruger is the ability to more simply take it apart, dry it out, and oil the internals if it should get drenched somehow.
I have a stainless 65-3, but I still use my 3" and 4" Ruger Service Sixes for trail use since I don't like to have to take the side plate off the S&W any more often then necessary for basic maintenance.
Of course, more then a few LEO's have carried blued steel handguns for years, out in the elements, and you see examples of those all the time that are still in wonderful condition - but it does take more attention to care and rust prevention then a stainless gun will.
I don't think I'd get rid of the 19 though, just as I won't get rid of my 65 - I just don't take it camping or hiking is all.