From the cheap seats....I've got no worries of bears where I fish... For me, the 10mm in a G20 would be first choice. I'm familiar with it, it carries easily with lots of rounds on board, and I shoot it quicker and more accurately than a S&W Mt gun in 45 that I shoot. OP mentioned several options and they would all work but I'm just so familiar with the G20 that I'd have a hard time going with anything else. I'm a big fan of the HPG kit bag for carry with a trigger guard. If you leave the side unzipped it's quick/easy access. Handy spot to carry other items as well.
Several folks opened it up to long guns. I can't see not using a handgun for ease of carry and access. It's something you hope to never use and I'd not want it to be continual trouble to carry. That said, I think a short, stainless 45 lever would be the easiest long gun to carry and use.....and someone who's not a "shooter" would likely do a lot better getting hits with it and no doubt those hits would have more umph than the same from a handgun:
