How many miles from Denver CO to Riverton WY?

400 miles taking taking this route:

1. Take I-25 NORTH, from Denver, to U.S. 20/26 WEST to SHOSHONI at EXIT 189 in CASPER, Wyoming.
2. Follow U.S. 20/26 WEST to Shoshoni, where 20 & 26 split; from Shoshoni, you will continue on U.S. 26 WEST to Riverton, WY.