@JSPEED and anyone else coming from the south; If you want more scenery on a short ride up, the ride up from Vegas along lake Mead is nice. Then on up into southern Utah. Along that route, If I had extra time, I'd take the back way in off of I-15 to 14 from Cedar City to 89 then 12 and then up and over towards Ritchfield. It's definitely the long way around but, IMHO by far the most scenic and exhilarating, plus it's the Scenic byway through Grand Staircase Escalante. Or take 14 over to 89 to Marysvale which runs parallel to I-15. I-15 is otherwise subpar boring..The ride from salt lake is pretty boring too and IMHO, S.L. traffic is horrendous at times. Lots of congestion and accidents. From Denver, it's pretty and scenic but much farther. Weekend traffic along I-70 can be insane as well especially around Denver ( heck it's horrible there anytime ) Then places like vail and the other resort towns can get crappy along I--70 especially if there's a chance of snow. Weekend Ski bum Traffic. Snails pace at times. I prefer taking the backroads of discovery.
Whichever way you go, Just know that UT 14 is forking amazing!