which way to go?

before leaving denver, i considered three alternate routes (see map below).  1) i-80 goes thru southern wyoming, salt lake city, and northern nevada.  since i've taken this way before, i wanted to try another route.   2) i-70 goes over the rockies in the middle of colorado, and thru the middle of utah where the interstate terminates and 'continues' as highway route 50.  this was my desired route because i hadn't taken it before and it got me off the interstate through nevada.   my plan was to spend a night in my van in central utah and a night in central nevada.   i got in bed satisfied with my choice of the second alternate...   that is until i imagined spending my first two nights in my van in the forecasted 15 degree nights of utah and nevada.  they were to be the coldest nights of the week in those high altitudes.   no thanks!   before i went to sleep i worked out some details on a southern / lower-altitude route.  3)  where i-70 terminates, it T's with i-15 which runs southward toward las vegas, cutting the NW corner of arizona along the way and dropping from well above 5000 ft to about 2000 ft.  the forecasted lows in las vegas were in the 40's...   much preferred conditions for trying out my van's bed...  then the route would continue by wrapping around the southern and western sides of yosemite.  yes, good, i was happy with that as the plan.