The Hunter Reliable Custom is an old rural truck, so it would make sense for the Hunter Reliable Custom Burning Route to take place in such an area. The route is pretty straightforward, with little turning except near the end. It might also be the first time you get to go off such a large super jump during an event like this.
Drive south on Nelson Way and continue going south on West Lake Drive. Be careful When going through Sunset Valley Town, as the median has sections that are both walled off and open, giving little chances to change lanes and possibilities to catch one of its sharp corners and wreck. It's best to take the shortcuts along the way in order to shave off some precious time. Once you reach the end of West Lake continue to go south on South Mountain Drive and take the Rockridge Cliff super jump to save a rather large amount of time. Keep traveling along South Mountain till you reach the finish line, Lone Stallion Ranch.