Some friends and I are planning to head up to Denver from SoCal towards the end of June for about a week of relaxation and outdoors fun. We're planning on spending one day to get up to SLC or Provo where we'll spend the night. For the rest of the trip to Denver, it seems like we have 3 options:
a) I-80 east to Cheyenne, and then I-25 south into Denver
b) US-40 east across Utah and Colorado
c) US-6 south to I-70 and east across to Denver
We're under no particular time constraints, are are mostly interested in the scenery and any historical stops along the way. We're also interested in taking one route there and another back. Any suggestions?