This is an excellent training path form MTN biking for the family, but it is definitely not a touring route. The path is badly beaten and there is not much interest by the California State Parks to renew it any time soon. The park is in itself very crowded and the main attractions are boating and swimming but it is definitely worth the try. Make sure you get there early as the park service closes the gates after the capacity is reached and believe me, it does.
That said, it has all the good elements of a mildly challenging training path like bumps, gaps, slopes and even some good sand baks generated by runoff from the San Bernardinos heavy snowfall. The path is not a popular trail and you can try different biking exercises with very few people around, even with the park up to capacity!
Try it and time yourself to see how you progress as I plan to use this as a common destination to get back in shape and as a prep-route for more challenging trails.