Travel to Grands Canyon to Moab

[Travel to Grands Canyon to Moab]

We are planning a trip from Nashville to Grand Canyon (South Rim) then on to Moab and Salt Lake (next summer). Looks like we take I40 most of the way to Grand Canyon

Wondering if any tips or lessons learned of which route is best, things to avoid or must places to see other than the obvious

We are driving a 40 foot diesel Allegro Open Road

Thanks!

[Trip from St Louis to Salt Lake-Yellowstone-Glacier]

Thanks, We are starting from Nashville, TN plan to go thru St Louis to Kansas City, 

[Trip from St Louis to Salt Lake-Yellowstone-Glacier]

We planning a trip to Yellowstone and Glacier but wanted to visit Salt Lake City first. We wanted to know how the drive from Denver (via i70) to Salt Lake would be in our 40 ft Allegro Open road diesel. I know one other option is I80 but how is the drive west of Denver on I70? Is the scenery worth the drive?, any significant grades to worry about?

What is best route option from West Yellowstone to West Glacier?

Thanks