It’s been about ten years since I was there, but yes, you can see a lot of amazing things in two or three days. Just being in Yosemite Valley, you’ll be in view of Half Dome, Yosemite Falls, and El Capitan, all must-sees. Try to make it up to Glacier Point for more spectacular views. If you’re feeling energetic, a hike to the top of Half Dome is unbeatable, but strenuous! Other good hikes are to Vernal Falls and Nevada Falls. By the way, the park is so popular that there are admission restrictions and finding a place to stay can be next to impossible, so plan ahead—and enjoy!