I put KO2s on my Outback last year. After 8000 miles (Alaska Highway to Poulsbo, WA, freeway to Birmingham, Alabama), the right rear was down to the wear bars, the left rear was almost as bad. Put on Geolanders. Drove home with them from Port Angeles. Like them better.
Don't get me wrong, I like the way the KO2s look and handle. The car looks totally butch with them on. But they were the wrong tire for what I wound up haveing to do, which was drive too many freeway miles on them. If all you are going to do is drive dirt and rock, probably much better. But the two highways you mentioned are not dirt and rock, they are gravel, and well maintained. Moreover, you are going to be driving thousands of highway miles to get to them. I would recommend getting something that is a M+S type tire, as it will be so much quieter and likely just as capable as what it sounds like you are going to do.
Best of luck!
p.s. This is all just for what it is worth. Others undoubtedly have different experiences. I succumbed to the look of the KO2s. Wish I had my money back.