From my experience:
Driving time: Eagle Mountain, Utah, to DL: ~10 hours
Ogden to Las Vegas: ~7 hours of driving
Las Vegas to DL: ~4 hours
(But Ogden is ~1 hour north of Eagle Mountain.)
I always drove the speed limit (~75 mph).
Last August I drove from the Ogden area to DL. It was our first "road trip" with then-DS5 and then-DD4; not knowing what to expect, we stayed one night in Las Vegas.
From my sketchy notes...
Ogden, Utah, to Las Vegas: (~7 hours of driving)
Left Ogden (on a Saturday) at 12:30 p.m. MDT
Arrived in Las Vegas at 7:00 p.m. PDT
- We stopped for a sandwich in Fillmore, Utah (45 minutes?)
- The drive (I-15) through the northwest corner in Arizona is very pretty! (Grand Canyon-esque)
Las Vegas to DL: (~4 hours of driving time)
Left Las Vegas (on a Sunday) around 12:00 Noon PDT
- There was a lot of traffic in Las Vegas around noon on Sunday
- The traffic (I-15) moved fairly well outside of Las Vegas
- The traffic was light on a Sunday afternoon in Anaheim
- Checked in to the Anaheim Camelot Inn & Suites
On the return trip, to make a long story short, we drove from Victorville, Calif., to Ogden, in 9 hours. (Of course that would be 8 hours to Eagle Mountain.) Add 80 miles (DL to Victorville), and the return trip to Eagle Mountain would be about 10 hours.
HTH