Stopped by the visitor center, listened to a brief ranger presentation about the trails and petroglyphs, then headed to the trails of our choice. There are several trails available of varying lengtghs and difficulties. There is a trail for everyone - one was literally a total of about 30 yards while another was a 2 1/2 mile hike through the desert. All of the trails are interesting and you are virtually guaranteed to see petroglyphs at them all. It is very interesting to scan the rocks, locate the petroglyphs, and think about someone carving the figures in the volcanic rock long ago. It provided a pretty cool connection to the past and I thought it was well worth the visit. Be aware though that this is a fairly low-key activity and people with little to no interest in history may actually find it boring. The only cost is $1.00 per vehicle. As several others have noted, this exhibit is outside IN THE DESERT so it is usually HOT. Take some water, wear a hat and some sunscreen, and enjoy the petroglyphs and hikes.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.