From Colter Bay, you could come down through Jackson Hole and follow US 191 across WY to I-80. Another route would be at Moran Junction, take US 26 across Togwotee Pass and through Casper to I-25, then to Cheyanne and I-80. (or continue S on I-25 to Denver) Driving down US 26, you could go S on US 287 through Ft. Washakie, Lander, to Rawlins at I-80. US 287 intersects the Oregon Trail at Split Rock, a historic Pony Express station.
If you stay on US 26 as it splits from I-25, you can visit Ft. Laramie and Scottsbluff, NE before US 26 joins with I-80.
I've done all these routes many times over the past 25 years, they are all good highways with much to see on each of them.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI