Whichever gun you end up choosing, it should be small enough that is does not interfere with your daily duties, powerful enough to get the job done, and controllable enough to allow for fast target reacquisition, and follow-up shots.
For this reason I like SAs, particularly the old model Ruger Vaquero. These guns have no crane to spring as is the case of DA revolvers, and the grooved receiver is as tough a rear sight as is available. Mine shoots pretty much to point of aim. The SA grip frame seems to fit my hand better than an N frame S&W.
I had the rear sight of a SBH fail, it fell off from recoil actually, and I replaced it with a Rough Country sight from Bowen Classic Arms. This rear sight is the toughest adjustable revolver sight made, the windage is adjusted by a pair of opposing screws rather than a single spring loaded screw. I lock-tited mine down to the lowest elevation where it is the strongest, and trimmed the front sight until it was regulated to my 325 gr load.
Appropriate loads IMHO are those that fire the heaviest, bluntest bullet that is available in that caliber that can manage 1200 fps. This results in loads that penetrate deeply, and produce a good wound volume with controllable recoil.
If I was looking at a new gun today I would give the Freedom Arms .500 Wyoming Express in a 4.5" barrel fixed sight version some consideration. If I was going to stick to Ruger, I would probably choose a .45 Colt or a .44 magnum in a Blackhawk with a short barrel if I couldn't find an old model Vaquero.
A retired helicopter pilot friend who did a great deal of polar bear work used a shoulder holster exclusively and carried either his M-29 or a Dan Wesson .44. I have difficulty reaching the butt of the gun when worn in a shoulder holster, so I favor a pancake style belt holster that I can wear strong side or cross draw. A belt holster though might be less than ideal for someone who spends much of his day in a seated position.
I think a holster for wilderness carry should cover the trigger guard, and have an open muzzle. If you draw the gun in a stressful situation, the covered trigger guard keeps willow branches away from your trigger, but also requires you to have your finger off the trigger until the muzzle clears the holster and is then presumably not pointed at your body. The holster should have an open muzzle to facilitate cleaning debris that will inevitably end up in there.