Grand Canyon is overrated
Salida, CO is a great little town where you'll find some great trailheads and the best part of the San Isabel National Forest. From there going up to Leadville is a good idea because it has one of the best views in the country. Pic for reference
then you can eventually work your way up to I-70 and drive over to Grand Junction. Its the most beautiful stretch of road in the country. Especially the portion through Glenwood Canyon where you'll be driving right alongside the Colorado River. A few pics for reference.
Its truly worth going up and out of the way of the normal cross country route aka I-40. I-40 is a god awful stretch of road and I would never recommend using it to go cross country. You'll get bored to death.
Now once you get to Moab that's where the fun starts. Its so much more beautiful than the Grand Canyon IMO. You get two humongous national parks, Arches and Canyonlands, in the same area. Some pics for reference.
Words can't really express how I feel about Canyonlands and Arches. I lived out of a tent for a week my first time out there by myself and it was the best week of my life. Since then I've been back two times and it never ceases to amaze me. The desert holds a special spiritual value to me that not many people can understand. Not a lot of people can appreciate the desert and that's understandable but it really is IMO the most beautiful terrain the world has to offer.
From there I'd suggest Grand Staircase which unfortunately I was only able to stop by for a few hours on one of my trips so it doesn't hold as much significance to me but its undeniably beautiful. Pics for reference.
My next suggestion would be Antelope Canyon, AZ just over the Utah-Arizona border. Once again somewhere that I wasn't able to spend a whole lot of time at but I would like to cause man it is beautiful. Pics for reference.
Real quick since I imagine you'll take the conventional route down I-40 definitely visit White Sands, NM. I shouldn't have to say much the pictures speak for themselves.
Its truly mesmerizing and feels like you're on another planet.
That's pretty much all I got since I've spent pretty much all my time in the four corners and honestly that's where you'll find the best terrain this Earth has to offer. My main thing on my trips is to avoid the tourist traps that everyone goes to since they generally suck from overcrowding and just generally aren't all that great hence my disdain for the Grand Canyon. I'd also go as far to recommend completely avoid hotels and camp out or sleep in the car the whole entire time. It adds a certain bit of rawness to the experience that makes it more memorable. For instance when I went for a week by myself I slept in my car or camped out every night and showered in gas station sinks when I was one the road or rivers when I was out in the national parks and besides being a great conversation starter it really made me feel truly free while I was out there. That's just really my personal preference since generally these trips mean more to me than just being a road trip. Its a chance for me to escape society for a little bit and live life how it was truly meant to be. I guess that's all I got just ask me anything if you want to know. And now some of my own pictures I've taken on my trips.