It all depends what your plans are at the Grand Canyon. If all you are interested in doing is looking over the side and then leaving, you should have enough time to do this and drive on to LV. If you want to look around a bit more then you should plan on staying in the area. Keep in mind you are starting this day in Sedona which is 1 1/2 to 2 hours from the park. The closest Hilton property is the Garden Inn in Flagstaff, but you will be backtracking. You could find a room at the small village of Tusayan just outside the park. Or (I recommend) drive 50 miles to Williams, AZ. I believe there are one or 2 Marriott properties there.