Julian,
the only part of the course that civilians are allowed to ride are the first half mile to the Del Mar gate, and then the part along the Old Coast Highway between the Las Pulgas gate and Cristianitos Road, about ten miles. The rest is closed. I am sure that in the Spring we will try to do some group rides on the course. This of course depends on having some of the Camp Pendleton Tri Team go with us, and right now, just about all of them are or are about to be shipped out. I'll let you know if and when we plan a ride so you can tag along also.
Mike Plumb, TriPower MultiSports
Professional Running, Cycling and Multisport Coaching, F.I.S.T. Certified
http://www.tripower.org