Need help connecting AZ/NV/UT/CO sightseeing spots...

Just a few quick thoughts as I skim this.

South Rim for sure to SEE the Grand Canyon; not just say you have been there.
Skip Four Corners
Cadillac Ranch is a good, basic place but heard it was up for sale.
I guess a dam is a dam but Lake Powell Dam does not compare to Hoover Dam.
I don't remember Moki Dugway being gravel.

Enjoy all these wonderful places - like others, we have been fortunate to live out this way and can spend time at them over and over.