When I was at UCLA, and after my bike frame cracked (and Trek took almost a year to warranty it), I switched to running. At one point, I was running daily 20 milers, usually hitting all the roads and trails up to Mulholland. I didn't have a car and was running from campus looking to do loops with dirt, so that explains the distance.
I haven't been back since 1991, but I love maps, and it was fun to look at the area.
For around 10 miles, I'd do something like this:
https://www.strava.com/activities/4798600623/overview
This was out of range from my base back then, but looks like a good loop:
https://www.strava.com/segments/2799841
Longer loop from Santa Monica:
https://www.strava.com/activities/2154025960/overview