Route recommendation

Thank you folks for your suggestions. I should have been clearer as far as time frames go but time is not a factor as the wife and I are both retired. We do plan to get some sightseeing in along the way and if we like an area, we would stay 4-6 days before moving on. We've traveled the western US over the years but this is our first cross country adventure in the rig. So any info, campgrounds, cities etc.,is greatly appreciated. Maybe different routes to and from would be best for exploration purposes.

Again, thanks for any info/advise you may have.