Lost In Las Vegas

Every time I visit Vegas I always have to do the Red Rock Canyon Park loop at least once. It's only a 15 mile loop but I want to add more mileage to it. I mapped out a route that starts and ends at Las Vegas Cyclery (8221 W. Charleston Blvd.). I would take Charleston Blvd. until it turns to Blue Diamond Rd. then enter into the park for the 15mi. loop, once out of the park I would continue west on Blue Diamond Blvd. towards the 160 and the town of Blue Diamond. Now this is where my concern is, I have two possible ways to get back to the shop either by way of Durango Dr. OR following Blue Diamond Rd. a little further to Rainbow Blvd. Does anyone know which one (Durango or Rainbow) is more cyclist friendly? and what mileage am I looking at by following either route? Any info. from the locals would be greatly appreciated! 😕