I am driving to Seattle next weekend and I have done this before, taking I-40 West to US-491/191 then 1-15 to 1-84 and so on. The second leg from SLC to Seattle is pretty straight forward, but I was wondering if anyone had any other routes they have drive from the Duke City to SLC? I used MapQuest and it gave me a route using US-550. Any advice would be great. I want to take the fastest route.