My advice after going on a few high elevation/wilderness September deer rifle hunts Colorado, is this- most of these areas don’t hold big bucks in high alpine basins like you dream of. In reality by the time mid September roles around the bucks have rubbed and heavy frost or dry alpine vegetation have pushed them down into the 10,000’ range where they become much harder to find. So I would adapt to the situation, if you aren’t finding bucks above tree line at 12,000’ adapt and move down in elevation. Best of luck