We are off topic again, but the best overnight options on that trip are Boise, Tremonton, Beaver and Page where the superchargers are at hotels. The hotel near the Beaver supercharger is kind of meh, but the others seem nice. I've stayed at the Tremonton supercharger a couple times.
I mentioned Page because if the weather is decent, driving Beaver->Page->Flagstaff-PHX will be faster and more scenic than driving Beaver->Vegas->PHX. But definitely check the weather because the Page route has some extremely high elevations that can get crushed by winter snowstorms. Also be sure to charge to near 100% if you attempt that leg because it's 185 miles and that could be tight in winter.