Heightened security ends a 40 year bicycle tradition
To assure the safety of US Marines, their families, and the civilians who work on Camp Pendleton, bicyclists using Stuart Mesa Road as an alternative to the I-5 freeway shoulder must provide identifying information for a background check 7 days in advance.
The on-line form can be found here: https://mccscp.wufoo.com/forms/camp-pendleton-bike-route-access-form/
You will get an automatic reply upon submitting the form, but no further reply will come from the Marines. Show ID at the Las Pulgas gate and the sentry will either wave you through, or direct you back to the freeway shoulder.
The I-5 freeway shoulder has been open to bicyclists between Las Pulgas and Harbor Dr. for decades. Signs will direct you through the rest areas and at the Harbor Dr. exit in Oceanside. If construction closes the I-5 shoulders, Signs will offer you a phone number to call to shuttle you and your bicycle!