For background, the distance from Trabuco Canyon in Orange County to Murrieta in Riverside County is about 15 miles as the crow flies — and there is a mountain range in between.
Camp Pendleton is South of San Clemente, which is itself south of San Juan Capistrano. You can see it on the map by scrolling down.
Pendleton is about 15 miles from both Trabuco Canyon and Murietta.