The rest of the miles are on the SART and sometimes I'll hit up Santiago canyon, back bay, or yorba linda hills. I do a self supported century about once a month, as the wife can handle things while I go play for 6 hours on a weekend..
You should go do GMR. To the village and back takes about 3 1/2 hours. That time is more enjoyable than the 6 hours it takes to do a century in the area you mention.
There is always the climb to the ski lifts to add another hour or so if you can't get enough enjoyment out of the GMR ride.
