There is a fee to enter but it is a nice hike through beautiful desert scenery. We hiked through a quarry/canyon and enjoyed great views of the surrounding mountains. This hike wasn’t too difficult aside from a few spots that required walking over some slick uneven rock that would break apart underfoot (maybe shale or slate) . Took our two dogs in the middle of the day in September which wasn’t a great idea although they loved modesta spring. I would recommend stopping after marker 13 and cutting back towards the visitor center for a more dog friendly walk in the heat of the day.