We visited Red Rock Canyon near Las Vegas the day after Christmas. Between Oct-May timed entry passes are required. Not sure if they weren't enforcing it on the day we were there or they just allowed a lot at a time, but it took us 45 minutes to get into the park. They need more signage at the road to indicate passes were required ahead of time. We didn't have a lot of time but we enjoyed a few hikes. It's close to Las Vegas so be prepared for it to be busy.
It's a one way scenic drive around the park.
