Koval Lane extends from Reno Ave. to Sands Ave. or for you tourists - MGM Grand to Wynn, two blocks east of the Strip. This small strip of road, only a few miles long, helps not only those who want to avoid traffic but also casino employees and delivery trucks which are needed to make your Vegas trip memorable. And it works - we once drove (separately) with a friend from the Tropicana to the Palazzo. We left together; we took Koval, she took the Strip, and arrived 40 minutes after we did.
You can access Koval by heading east through main roads such as Tropicana, Flamingo, and Spring Mountain - then just nip along to whichever intersection of the Strip you need (you'll hit the car parks the back way).
Just beware of the area between Tropicana Ave and Mandalay Bay Road as it is a 25 MPH zone and I have seen many cops hiding behind bushes trying to make their daily quota.
So be savvy! Don't get stuck in the mess that is the Strip. If you take Koval, you'll be glad you did.