Yeah I highly suggest the Santa Ana bike trail… Super awesome ride!
I put up some pictures when I did it last summer here http://swimbikerunsurf.blogspot.com/...o-my-first-half.html
It’s got an awesome tailwind on the way up the river and a pretty strong headwind on the way back to the coast depending on the time of day.
More info here: http://santaanarivertrail.org/home.html
Most of the year there is a tailwind going up the Santa Ana River, However with Santa Ana winds blowing super strong lately, that may not be the case. I rode on it today and there were freak 30 mph winds blowing out of the East.
x 2 on the San Joaquin Hills Rd. Laguna Canyon is also very nice and you can link it out to Santiago Canyon for a big ride. The Canyon is a lot of fun. A search for these spots on Strava or Mapmyride should give you lots of options.