I made this route for Nick but figured I'd post it here as a public service. In that spirit I think it best to provide some guidance to prepare you for what you'll encounter. The route starts at Rapha in Santa Monica, mostly because that's my default starting point but also maybe you want a coffee, some retail therapy, or to visit with some MAMILs before or after your run.
Route:
https://ridewithgps.com/routes/41854878
Mile 0.5: stay on the pedestrian walkway to descend the California incline, be aware of cyclists and other vehicle types (and inattentive tourists gawking at the Pacific), once you're on the beach path stay on the pedestrian side until …
Mile 1.9: descend the stairs and go through the tunnel to cross under PCH (apologies for the odor, may remind you of the NYC subway)
Mile 2.2: for the bulk of the remainder, the sidewalk is intermittent so just plan to run in the street, not as dangerous as it sounds
Mile 3.9: the road appears to end but there is a path over a bridge and through a gate that allows you to continue
Mile 4.0: unfortunately, you have a tenth of a mile along Sunset Blvd. to get to the road that enters Will Rogers. There might be sidewalk, I don't know.
Mile 4.9: beginning of the dirt and a scenic loop around Inspiration Point.
Mile 7.6: while it looks like you're about to turn onto Sunset, to your right there's a single track that brings you back into Will Rogers.
Mile 8.6: again, that same 0.1 mile along Sunset that brings you back to the gated bridge
Mile 10.2: as a final leg burner, a set of stairs that bring you up to the bluff above Santa Monica canyon, very popular workout spot
Enjoy!