I spent four nights in Yosemite National Park, and I didn't want to leave. If I had been going back to normal work, I may not have, but I left to spend two weeks of observing.
My requirements were to see giant trees and waterfalls. The first area that I visited was a grove of giant sequoia trees, Tuolemne Grove. It was awesome. You just walk along the forest path, then through the trees there's a tree that's a slightly different color. You get a little closer to it, and then you realize that this thing is bigger than everything around it.
I have a bunch of pictures of big trees that do nothing to capture their size.
The next stop was a view of the famed rock face for treacherous rock-climbing, El Capitan, from the floor of Yosemite Valley.
While standing there, I turned around to see my first Yosemite waterfall: Bridalveil Falls. I had the opportunity to climb around on the boulders that were at the base of the waterfall (but not directly under the water). I took it...even though there were signs warning people against it and I had the worst sneakers on possible for climbing on slick rocks.
For two nights, I stayed in Yosemite Valley. I would equate the experience to staying at a resort. There are restaurants, hotels, and way too many people. There were lots of waterfalls, so the hikes from the Valley floor were stunning. I hiked to the front of Vernal Falls. There's a series of stone steps that leads up to the top of the waterfall, but crosses right in front of it on the aptly-named Mist Trail. I stopped in front of the waterfall as my knees were already killing me. The view from above would not have been comparable.
Yosemite Falls were also stunning.
There was lots of driving from overlook to overlook searching for the best view of Yosemite. All of them were equally awesome.

The next two nights were spent in the mountainy part of Yosemite. There was more hiking and fewer people. Since this was where the waterfalls started, there were some nice rivers and streams. A highlight was lunch next to a pretty lake. I enjoyed it up there more except for the mosquito bites. Even with bug repellant, they got me.
I saw some wildlife while there. I saw a bunch of mule deer, some elk (which I described as huge deerlike things), coyotes, huge birds of many varieties, various butterflies, and small woodland creatures (perhaps a woodchuck?). No bears or mountain lions. I hiked in fear of both.
The accommodations were platforms with plastic canvas tents. Inside were cots and a wood stove (only in the mountainy tent). There were communal restrooms. The lodgings weren't terrible, but I can't call it camping.
I can't believe I didn't visit Yosemite last summer; that was a mistake.