Probably best to avoid this route during this time. Won't affect weekend rides. From  Seth Cutter, our Bicycle Transportation Coordinator at Caltrans :

QuoteGood Afternoon,
The U.S. Marine Corps is planning to close the Camp Pendleton Bike Pathâ€"the only bike access between Las Pulgas Rd. and Basilone Rd. along Interstate 5 (I-5)â€" for military operations between this Monday, Jan. 25 and Friday, Jan. 29, 2016.  Under normal bike path closure circumstances Caltrans would open the freeway shoulders in this segment to bicyclists, however there is a construction project that has closed the shoulders of I-5 in that segment.  Caltrans will provide a 24/7 on-call shuttle for bicyclists to pass through the closures in the I-5 corridor between Oceanside and San Clemente.  The phone number for the shuttle is (619)385-3267.  There will be pick-up locations at the Las Pulgas Rd. parking lot for northbound cyclists, and at the south end of the Old Hwy. 101 bike path at Basilone Rd. for southbound cyclists.  Those locations will serve as drop-off locations for the opposing directions of travel.  Signs at both locations will include the shuttle phone number.  Please share this information and make your plans accordingly. We apologize for any inconveniences in advance.

FYIâ€"Staff on-base at Camp Pendleton have indicated that their access policy for bicyclists will change effective Mar. 1, and not Feb. 1 as many feared would happen.  The Marine Corps is establishing a method to allow cyclists to register and apply for access to Camp Pendleton and I will keep persons on this contact list informed of any information related to that matter as it becomes available.

Feel free to contact me if you have any questions.

Sincerely,
Seth

Seth Cutter
Bicycle and Pedestrian Coordinator
Associate Transportation Planner

Multimodal Programs Branch
Caltrans District 11 Planning Division
619-688-2597
www.dot.ca.gov/dist11/departments/planning/pages/bicyclepages.htm