OK we have a winner!! Here is the map of the actual route......If you tried to use google, the route google uses was not the same....I-15 is under construction and you must detour down Las Vegas Blvd. and the get back on the freeway

Anyways, the answer 61.3 Miles.

The closest guess was 60.8 Steve Blust LM-4120-79. Congrats Steve, I will email you for your address. Thanks to everyone who guessed