No head for heights whatsoever and doing the above road trip on the i15. Would really like to know if this is a flat route with no high roads to travel.
Hopefully someone who's done this exact trip can tell you more about how it feels. I'm not sure if there is any alternative route that would be flat, since this is the main route most people would take.
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This is a terrible city to drive in on the Interstate. Call the hotel ahead and get exact best route. High speeds. Be safe.
I did from Salt Lake City to Reno and on to Sacramento in a 1932 Plymouth where we did not want to climb mountains. (This was back in the 60s). I do not remember much mountainous between SLC and Reno, but coming down into Sacramento was very steep (although not scary).
I have done this route several times, and the only spot that makes me nervous is when you pass into the corner of Arizona from Utah, you go through a canyon, so its windy roads. So I just stay in the right lane and take my time.