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.