We parked at NCAR to start this trail. Following the Mesa Trail, it is a short hike to the actual Mallory Cave Trail. When you get to the actual trailhead, you hit some immediate switchbacks taking you up. They aren't too bad though.
The trail was pretty popular and there were a decent amount of people there around noon. The trail also connects to a lot of bouldering/climbing spots. We saw lots of climbers. It was cool (and scary) to watch them climb up the rocks! We stopped several times to check them out.
Since I love exploring while I hike, we also did a little climbing of our own. We climbed up a large rock which climbers were bouldering up on the other side. We couldn't climb all the way to the top, but still got a good view from where we did manage to climb. It was fun! We also took a little side path to another view point. It was quiet over in that area, besides a river or waterfall we could hear but not see. The view was pretty (first three pictures in second row)!
When we got to the end of the trail, there is a narrow path up a rock wall you have to climb to get to the actual cave. There were a lot of people at this spot waiting to climb up or climb down. Since the path is so narrow, you can't climb up while someone climbs down at the same time. We had to wait a while for our turn to climb up.
The climb itself is not too bad, but going back down is a little trickier. Several people on the trail decided not to climb up, but I think it is worth a shot, because the view is pretty great. After the climb, you are basically at the cave. Since it was closed, we didn't get to explore inside (it is closed because of nesting bats).
This short trail was nice, even though the cave was closed. We saw lots of dogs and families on the hike. The views were pretty and the little side trails and climbing areas made it a lot of fun. A good choice for a short adventure in Boulder.