When are you planning to drive this?

What are you concerned about? what qualitites are you looking for?

The best way would be the first one.....

I-15 to south of Provo, take Us 6 to I-70 then i-70 west. i have driven this numerous times. the road is mostly 60 mph+. the only issue is right after leaving I-15 when you have to go over a pass but there its more of an expressway that is well maintained because this is a heavy semi trucking route. There are speed zones around Price...a town you pass through just south of Price that is a speed trap waiting. After the mountain pass the road is pretty flat so south of Price when there isnt speed zones its 65 mph. From here I-70 to Vail is pretty flat with not much climbing or passes you have to go through.

2. with the I-15/US 50/I-70 route...there isnt much of a mountain pass you go over. at that point there is a break in the mountains that 50 cuts through. The stretch on I-70 between here and when you meet US 6 is an interesting drive because you are cutting through the Reef so there are interesting rock formations and a few view points you can pull off on the highway. This is a longer drive. Maybe an HR or so.

If a snow storm just hit or you are uncomfortable with going over a mountian pass....then as an alternate use this route.

3. this is 64/13. On 40 you go through all the ski areas then to Vernal, then south through rather dull remote areas. In the winter the road from US 40 to I-70 I wonder how well its maintained.

4./5. are also going to be pretty dull and flat drives. Along I-80 near rock springs you have a side trip through Flaming Gorge but outside of that not much but pretty flat.