Hey guys, at the end of June I am going to be going on a four day/three night backpacking trip in the Eastern Sierras in California. It's looking to be ~23 miles give or take with 5k feet of elevation gain, all of it is going to be at 8k feet above sea level or higher. The only overnight experience I have is a 21 mile trip in two days with ~4k feet of elevation gain back in October, but it was on the East Coast of the US and not at altitude. I live in Massachusetts so I don't have much access to high altitude anything, so how can I go about preparing for this to make it as painless as possible? Thanks in advance for any help and or criticism!