Any pistol can suffer reliability issues due to mud, dirt or debris. Best thing is to protect whatever you decide on with a flap holster. They are surprisingly convenient for unholstering and reholstering. I have a couple of leather / nylon flap holsters from Idaho Leather http://idaho-leather.com
that have been very durable and didn't break the bank. Ben will make one up for any gun you decide on.
I'd advise that the .44 mag or .45 colt are at the top end of what you want. Carrying the unnecessary weight and bulk of a .454 or larger revo gets to be a PITA fast. Don't rule out the autoloaders either, plenty of power in a convenient package. Heck, my SR40c gets lots of woods time, even though larger guns are available. My fave is the Lipsey's BH .44 Special, - enough power for anything around here in a reliable, convenient package.