It's LONG...take some time to absorb the info!
I think I have decoded the Arizona portion of your trip. We can expound a bit more on the surrounding states, but we'll work through our part of the wilderness first.
I created this Google Map link :click:
http://goo.gl/maps/T1QDq starting outside of Vegas, then working your way in this direction.
So, this is as long as it takes you - I'm guessing three to four days for someone to do it the first time. One point of reference that can't be stressed enough. Much of your trip in AZ will be in what's called "high desert". You can be a few thousand meters above sea level, but the humidity is very, very low. Up to a liter of water an hour you'll need to consume to stave off dehydration, which tends to sneak up on you quickly. With all of your prior travels in California headed this way, you will have been in desert conditions the whole time. Adding in a bit of elevation can really exacerbate dehydration issues.
The trip starts at the Hoover Dam
http://www.usbr.gov/lc/hooverdam/service/DamTour.html where you'll see what it was like back 80-odd years ago to create one of the seven industrial wonders of the world. If you're into industrial history, it's worth the three or four hours to take the tour.
Taking either one of the two major routes to get to Laughlin, great place to stay - and be close to hit our next stop, Oatman, AZ. Laughlin in a gambling town. In August, as Brian mentioned, it'll be between 40C and 45C (yeah, no joke - high as 50C at times!) in the mid to late afternoon.
You'll want to try & be in Oatman around 1330 or 1530, if possible - the locals do a gun fight that's neat to see what the 'law' was like in the Old West.
Next, the ride out of Oatman will continue along a stretch of old US-66 toward Kingman, AZ, yet another 'large' community that grew up around the railroads and well as the highway (the rails were better than the roads out here by decades...). There's a gas station that you'll want to get a couple of photos of.
East of Kingman, the stretch of US-66 that you're looking for. Stop there at Peach Springs; do you recognize it? Several of these locales were Disneyed-up in their hit movie "Cars"
Brian mentioned Seligman...another stop along the highway, and another tale of life out on the road.
Now, my map I tossed in a detour that'll take you up and over the mountains toward the mining town of Jerome, AZ. Artsy, laid-back community along the side of the mountain, close to Cottonwood & Sedona.
From there, back toward Flagstaff via Oak Creek Canyon, and where both Brian and I think you're headed; Meteor Crater.
Big hole in the ground.
Back toward Flagstaff, then off to the South Rim of the Grand Canyon. You can spend as much as a few hours, or as much as a few days to wander around. ProTip: Go a bit east of Tusayan; plenty of spectacular views, but without quite as many people. Several million a year visit the area - this will take all day.
Out the east end of the park, toward Kayenta. There's not much there at all. You'll now head into the Native American world; like none other you've ever seen - and you will take hundreds of photos of the breataking views you'll have along the road.
I'll stop here and let Brian fill in some of the gaps I may have left, but he's been up that way more recent than I have, so he'll do a much better job that I will.
(...this is fun. Write it once, then point back to this thread in the future for others who ask the same questions you are!) :thumbup: