I'm coming in late to the party, but given I love this area of the states, I'll chime in with my thoughts, which likely will mirror some of what you've read already.
First off - I personally don't have a problem with going to "iconic" sites that have been "over-photographed" - there's usually a reason those places are iconic, and there's nothing wrong with getting your own version of them, and then, should you have time and another chance at the area in the future, venturing further off the beaten path to discover some less-shot areas. I sometimes find that by going "contrarian" with lens selection at the popular places, I get some different shots (example: I like to shoot longer glass at the sand dunes and at Bryce, whereas most people bring super wides).
Basically, if I could have only one trip to the Southwest in general, I'd want to do:
My "Don't Miss" list would be:
- Sunrise at Dead Horse Point State Park (near Canyonlands)
- Sunrise at Mesa Arch in Canyonlands (be there EARLY, claim your spot, you won't be alone, and it's tight)
- Sunrise and Sunset (both) at the Sand Dunes in Death Valley (tips: park closer to stovepipe wells on the side of road, don't park at the "parking lot" area, and for gods sake, bring water and gatorade like you don't even know, even for a short mile into the dunes - this place can get brutal)
- Sunrise at Zabriske Point in Death Valley, even though it's been done a lot. Still knocks me out every time, and I'm on my 8th visit later this year myself.
- Opening couple hours in the AM at Lower Antelope Canyon near Page on the photographers pass. (I'd skip Upper Antelope entirely, but that's just me)
- Sunrise at Point Imperial at the Grand Canyon North Rim (I'd skip the South Rim entirely, but that's just me)
And then the rest would be:
- Sunset at the Cape Royale overlook at the Grand Canyon North Rim
- Sunrise at Bryce Point at Bryce Canyon (be there EARLY, expect massive crowds from the early arriving tour bus - still, worth seeing before you die)
- Sunrise at the Windows section of Arches NP
- 11:15am give or take at Horseshoe Bend overlook, also near Page. Watch the freaking edge - no guardrail, long, long way down.
- The major overlooks of Canyonlands in the early pre-sunset evening hours
- Sunset and post sunset at the Badwater salt flats in Death Valley (see my earlier comment about water, water, and more water, and then more water)
- The rimrocks hoodoo's area between Page and Kanab, off 89. A short (.8 mile one way) to the hoodoo's, glorious late afternoon / early evening light on the couple formations there - actually one of my favorite areas to just work and relax, without horrible crowds. Bring GPS as you can get tangled up finding your way out if you're not paying attention.
- A run through Zion both in the early and late hours.
- The run on hwy 12 near Boulder and Escalante, UT
- A stop by Jacob Lake Inn on the way into the North Rim, just because the place is cool. Okay, I'll fess up. It's because they have really good, and really big, cookies. (Be advised it's 1-2 hours from there to any of the big viewpoints, but it's a nice place if you don't mind the travel distance)
I'll echo what others have said about distance, I-70 (truly magnificent piece of interstate from where 191 hits it from Arches to where it terminates at I-15 to the west - some amazing scenery for sure), and being careful where you stick your hands regarding snakes and other critters.
I'll also say that by far the biggest piece of advice is this: WATER and emergency supplies. I had a breakdown earlier this year out that way, and even being just a short distance from Vegas, it took nearly four hours to get a tow truck to get me back to the rental car facility and get another car. It was well into the 100's, and that was a long, hot wait. If you're in this scenario somewhere remote (say, Death Valley) without cell signal, you better damn well have at least a days worth of water and some food to keep you going, or you might be beef jerky for the buzzards by the morning. Particularly in Death Valley, water is key and critical - that park is NO JOKE when it comes to heat and potential danger. I'd advise buying at least 12 liters of water right off the bat at the nearest convenience mart as you leave the rental car facility at McCarran (or wherever you're flying into).
Also be SURE to check in with the ranger stations for road conditions. The Kanab, UT BLM office is particularly nice - and right off the main road in Kanab, and worth stopping by if you're in that neck of the woods. (There's also a good barbershop a block or so away if you need such service). The roads vary a lot - a dirt track that is fine one month can be brutal the next. When I was in the area in May, Cottonwood Canyon road was said to be brutally impassable, but the word I heard was by June it was better again. And of course, don't even remotely think about the slot canyons if there is any flash flood danger.
Lodging wise: I like the Quality Inn in Cedar City, Ruby's in Bryce, the Sleep Inn in Moab, the Quality Inn in Page, and your pick of casino's in Vegas