Red Rock Canyon requires a reservation to get in between October 1st and May 31st, for entry between 8 a.m. and 5 p.m. For a timed entry reservation click here.  Since the Scenic Drive portion of the tour is a one-way loop, you cannot backtrack if you pass a stop along the route. So if you skip a stop, or want to revisit a stop later in the day,  you'd have to make another reservation (if one is still available) in order to go back around the Scenic Drive to reach it. If you are entering Red Rock Canyon between 6 a.m. and 8 a.m., you do not need a reservation. Nor do you need a reservation between June 1st and September 30th.