Just Walk!
Some advice for any one is who is ever in their predicament, the simple solution is to take whatever food and water you have, and walk back on the road you drove in on. Start walking ASAP. Whether its 50 miles or 80 miles, young people CAN walk that far on a road in flat terrain. Walk all night if the heat is too great. You may reach cell range or another vehicle the closer you get to pavement. Any one who thinks this can't by done, watch "Alive" (the film about the Uraguayan rugby team stranded on a glacier at 15000 feet in the Andes after their plane crashed).
Also, driving that far off pavement without at least several gallons of water and 3-4 days supply of food is playing Russian Roulette. The excursion "leader" for a complete fool. Making some simple preparations and making smart choices saves lives in these situations.