You can cross the Wasatch Mountains at Parley's Canyon, just east of Salt Lake City. The elevation at the pass is 7150', so get your altitude early (do NOT try to out climb the canyon!), and plan to cross at about 9500' or above. Early in the day is best, because if the winds pick up like they often do later in the day, it can get pretty bumpy, like in awful!
Then follow I-80 eastbound all the way to Laramie. That will take you past Evanston, Rock Springs, Rawlins, and Medicine Bow. Don't turn south until after you pass Elk Mountain east of Rawlins, in other words, don't try to take a short cut by turning southeast sooner than that. If you're not familiar with the country, it's easy to get discombobulated. At Laramie, you'll continue southwards essentially along US 287 over the ridge to the south and on toward Fort Collins and Denver, if that's where you want to go.
What sort of sight-seeing are you interested in? I know Wyoming and northern Colorado well, but everyone's interests are different.
Cary