Santa Cruz caves are very near to UC Santa Cruz as well. Empire Grade road if I remember correctly. Many caves in the area. CEMEX property has land grants, caves, hiking, biking ect. But the cave are hidden, no trails or signs. Locals know where it is.
This article mentions the cemex property and caves
https://ww2.kqed.org/quest/2012/11/20/shadows-and-spiders-a-secret-cave-in-california/