Parking will be a mess, if possible I recommend parking at or near a Sprinter station then riding from the Nordahl station to the start. http://www.gonctd.com/wp-content/uploads/Schedules/SPRINTER-Schedule.pdf
https://ridewithgps.com/routes/26486106
There is a train leaving Oceanside at 6:33AM and San Marcos Civic center at 7:13 arriving at Nordahl at 7:21AM.
There is a parking garage at the San Marcos Civic Center (City Hall and Library) close to the Sprinter station at Mission and Woodward St.
Ride starts at 8AM, sign up here: http://ranchoscycling.org/events/
Our Cruiser long Route: https://ridewithgps.com/routes/26381541