Northeast of Newport and Laguna Hills, a scenic 14 mile mountain bike route up Santiago Peak combines Maple Springs Road with Main Divide Road.
To reach the mountain biking trailhead from Newport, head northeast on SR 55 and exit east onto Chapman Road (aka Santiago Canyon). Proceed on from a dozen miles and turn left on Silverado Canyon Road (aka Maple Springs Road) and park at the gated end.
Continue riding up the road to the intersection with Main Divide Road, and turn right towards Santiago Peak.
Note, there is an unmaintained trail called Santiago Peak Trail that also runs up to the summit.
Overall, Santiago Peak - Maple Springs is the 7th most popular mountain bike trail of all 132 mountain biking rides in California.