The Grand Canyon, yes, and I highly recommend the trip. The North Rim is amazing and it was the first trip where I wasn't ready to leave when the time came. Bonneville Flats I haven't seen in person, but my husband drove it on a motorcycle trip in the 1980's and described the overwhelming smell of salt and the flat, white expanse as far as the eye could see.
If you've seen the movie The World's Fastest Indian with Anthony Hopkins - that's the Bonneville Salt Flats. Good movie, too.