forget Ortega, too much traffic. Palomar is popular but if it is slightly wet it will never get dry because of the shade and elevation
The absolute best riding road in the world is called Montezuma Hwy near Borrego
Another good road is so called Palms to Pines -- between Palm Desert and Banning.
Heck, I even have a map of all the roads:
http://maps.google.com/maps/ms?hl=en...mid=1197597712
If you feel adventurous you can try MEX 2 across the border (cross in Tecate - no line and no crime)