From SLC, one could take I-15 to I-40 then cross over to UT24 to Hanksville, but it is definitely much longer of a trip. US-6 from Spanish Fork to I-40 is four lane for a good portion of the drive to Soldier Summit, and is 65mph the whole way except near Price.
I-15/I-40/UT-24 : approximately 369 miles
I-15/US-6/I-40/UT-24 : approximately 231 miles
There are plenty of other variations to these too if one wanted to mix it up even more.
"So I was sitting in my cubicle today, and I realized, ever since I started working, every single day of my life has been worse than the day before it. So that means that every single day that you see me, that's on the worst day of my life."
--Peter Gibbons (Office Space)