The California parks and trails application built on the top of my another free app, My POI KML Map Integrator, which means that you will be able to open your own KML and KMZ files and navigate to selected waypoint, both online and offline (if selected navigator allows offline navigation).
In addition to this, California parks allows you to download different collections of the waypoints, including California state parks
and federal RIDB databases.
Currently it have following POI collections available:

California state parks
recreation.gov CAMPING
recreation.gov HIKING
California Hot Springs
California Hot Springs USGS listings

Total number is 2183 waypoints in all collections (but many of them are duplicates).