Marty: No permit is required to day hike R2R. But arranging the car shuttle or transportation can be tricky. I got lucky, and shared with Julius S on this one -- Julius and Co. got their permit over 6 months in advance, since they stayed overnight near the north rim, then two nights near Phantom Ranch in the canyon, and then another motel night on the S Rim.

I myself just traded cars with them, spent a night in a National Forest site before the hike, hiked across and then drove almost to Las Vegas and spent a night in a motel in Mesquite, NV afterward.

Read this entire thread. It was a really unique experience for me.