I don't think that is possible. East Camino Cielo (the ORV part) ends just beyond Divide Peak (gated). Looks like Matilija Canyon ends at what may be part of Murrietta Juncal Rd. That has always been gated; I got a federal trespassing charge in the mid 70's when I rode from Camino Ceilo down a ridge line to Jameson Lake. Used to be more roads open, they have been closing them down because of environmental and budget constraints. If not for the ORV designation (read 'money') I believe those sections would have been closed years ago.
But hey, if you can find a way, PM me!