I did part of your trip last year. Enjoyed the first couple of days @ Speed Week in Bonneville, then drove straight to Moab. A nice scenic drive, no major climbs or passes, seems like about 6 hours from Wendover to Moab via hwy 6. If you are traveling I-70 from Denver, take hwy 128 to Moab. It follows the Colorado river for a long way and is a wonderful drive. Spend plenty of time in Moab.
St George seems like a long way out of the way for that schedule.
If it's you first time to Bonneville, take a big hat & sunscreen under your arms and any where else the reflecting sun can reach.It is a blast.
gus