I would go with the 1911 followed up with a long gun. I am not the best with the long gun ideas, but the handgun I think I can give you a thought or two.
I would get 1911 with 230gr. FMJ. Now I know everyone is going to scream and say you need a hollow point, but the reason I would go with FMJ is I want to penetration.
The old saying is you might get a 9mm to expand to .40, but a .45 cant shrink.
I want to make sure that when that bear or even person is coming at me the twigs, brush, bone, outdoor wear, and tense muscle that the bullet will have in the way before hitting that organ or whatever, I basically want it to get there. I want the round nose to slide throw the leaves and branches. Also if you are me you are going to just empty your mag into a running bear so no matter what at least one of the bullets are going to hit square weather JHP or FMJ. Also you will be only using your handgun if your rifle is down or you ran out of rounds. There really is no time for a reload. Just drop the rifle and go for the handgun.
Now this is all hypothetical and I have never been in a mountain fighting situation. So maybe everything I just said it dumb but in my mind if the FMJ is going to make me feel safer than I am going to load that. Thats really the bottom line whatever you feel comfortable with.