Camp Muir is at just over 10,000', high on the southeast side of Mount Rainier. It sits at the crest of the Muir Snowfield, about 4.5 miles and 4500 vertical feet above Paradise. It's the standard overnight spot for folks heading to the summit and a strenuous day hike for the rest of us.
The only thing that slowed D on the way up was his old man, since he was patient enough to stop and wait for me to catch up every few hundred steps. But a little more than four hours after leaving the parking lot, he arrived at Camp Muir. I staggered in ten minutes later. We munched on our salami and cheese and most of a package of cookies, and then headed down, sliding down chutes in our rain pants where it was steep enough and walking the rest. It was just over two hours back down.
Camp Muir is a dark speck between rocky hummocks just to the right and above the center point of the bottom picture - the tree is pointing just right of it. If you look carefully at the expanded image, you can see the tracks leading up the snowfield towards it.