First off, thank you both very much! This is very helpful for planning our trip. I wanted the most efficient timing for this trip, but want to see as much as I can, while taking in the beauty of everything. I am thinking of either skipping Hoover Dam, Havasu Lake, or Zion to increase time at the Grand Canyon. I don't even know what I'd do at Zion, but I'm sure it is breath-taking... What do you think?