across the north side of the LA basin to Pasadena and connecting to Venice Blvd, which is a class II (bike lane) route from downtown Los Angeles to the beach at Santa Monica.
I had earlier looked at using maybe Olympic or Pico since Venice has soooooooo many stops. I never rode any other street there besides Venice to know if they're any good, although I did follow one on the satelite view and now I can't even remember what street it was. It looked relatively safe as far as things like lane widths go. Can you comment?
There are several north south Shared Use river trails that can be used to get to or near all the towns in the LA basin from this route.
It probably should be pointed out that these are class-1 paved bike trails (and the signs specifically say "BIKE TRAIL"), where, although you will occasionally encounter pedestrians or even horses that fail to stay to the side, for the most part they really are bicycle freeways (autobahn? bikebahn?), worthy of all the speed you want to give it, not like the beach trails which are covered with sand and clogged with strollers, dogs, toddlers, etc.. With a terrific tailwind, I once did five miles in nine minutes on one of these trails, going 35mph most of that time but slowing a little for the underpasses, and seeing only two people in that stretch, both men off to the side with their jaws dropped to see a bike going so fast without a downhill. I would have been glad to go another 10mph if the tailwind were gale force.