I used to carry a Glock 20 on the ranch in Texas. Shot a few hogs with it at close range. For me, it was the only thing that seems to drop them in their tracks. They just seem to give up and lay down
You shouldnt have much problem with the mountains, except possible altitude sickness, which can hit anyone. Years ago, my doctor told me to start taking vitamin B a couple weeks before going above 12,000 ft. It seems to help
Haven't shot either scope, but I do have a similar rifle (7-300 Wby) which requires a very snug hold. I shoot at 18X for PD's because anything more than that picks up my heartbeat....
I tried the Benelli 826. I like the looks and it is only a tad over 6 pounds. I is an amazing shotgun, but kicked the snot out of me if I didnt get it mounted just right. I sold mine, but they are definitely worth a look.
Another vote for Scorpyd Ventilator. I keep "wanting" something new, but cant find anything that would get the job done better. Fast, quiet and accurate.
It has been years since I went, but the area around Zortman, Montana was the best PD hunting I ever did. There was public land and you could buy a license to hunt on the reservation for a reasonable price