While you can complete the entire 33 mile Rim Drive, the only portion that is vehicle free is the East Rim (indicated by the yellow highlighted line). All other areas of the Rim Drive will have vehicles (indicated by the blue highlighted line). You'll notice, as the Key indicates, the orange dotted line is the Shuttle route. Please prepare accordingly.
You can export the route to your GPS by going to https://ridewithgps.com/routes and choosing the export option.