Monday-Wednesday: The main trailhead parking is extremely busy, so plan on having to circle and snag a spot as hikers finish their descent. It requires either a Red Rock Parking Pass which can be purchased ahead of time, or with credit card through a machine at the trailhead, or if you have the America the Beautiful pass  it also covers parking.  Thursday- Sunday:  There is now a year-round shuttle system in place to help the neighborhood with traffic and parking issues.  This means there is no parking available at the trailhead during hours the shuttle is running, so if you want a sunset session, you will either have to take a connector trail with a longer hike, plan for Monday- Wednesday, or arrange a pickup after the shuttles have stopped running.  For current shuttle schedules, visit Sedona Shuttle. Quick pro-tip on getting there: For Monday-Wednesday when you can park yourself, be sure to enter "Cathedral Rock Trailhead" into your gps. Many people have accidentally only put in "Cathedral Rock" and it will take you to a side road with that name a few miles away.