I am planning my family summer road trip. We plan to fly to Salt Lake City then visiting Arch NP, then take the I-70 to Rocky Mountain NP. On the way back to Salt Lake City, we want to take a different route. Is US 40 a good option? How long does it take? Anything spots worth stopping along US 40? Thanks in advance.

By the way, we've been to Beartooth Highway and Yellowstone...