Does anyone have any advice on what routes to take on this itinerary? I have mapquested it, but I'd like to make sure we take the most scenic roads if the time difference isn't TOO outrageous.

You don't have too many choices of paved roads.

Take a look at a map.

From east - west you have 70 a bit further north, 12 in the middle and 89 partially in the south of Utah.

That's it.

The most scenic will be 12 between capitol reef and Escalante.