Definitely consider visiting Canyonlands, it's like a sister of the Grand Canyon but less crowded. There's plenty to see and do, including viewing roaming bison, looking at underpasses, and great views of the needlepoints. There's also a section where there's primitive trilobytes, and depending on when you visit, you'll be able to see the rock that appears to stand up on a tiny tip. Really worth seeing as it contains hundreds of canyons, each with different textures, depending on which side of the park you start driving into.