Northwest of Las Vegas in the Red Rock Canyon National Conservation Area, the 9 mile Mustang Trail on Keystone Thrust is a great desert mountain biking singletrack past cactus and sage over granular red dirt.
To reach the trailhead from Las Vegas, head south on US15 to Blue Diamond Road (SR160). Head west on Blue Diamond Road (SR160) for 15 miles to unmarked parking area on the right.
For some nightlife in Vegas, try Double Down and Drais.
Overall, Mustang Trail is the 1st most popular mountain bike trail of all 15 mountain biking rides in Nevada.