One of the things inherent in military service is TDY that also requires short term relocation. Personnel are advised to consult their base housing office but they may or may not be prepared to provide information regarding off base temporary term civilian housing. This is where the help of a local Realtor comes into the picture. You want to be sure to check if your base housing service maintains a list of recommended real estate agents in the cities near your TDY. Southern California has unique challenges in traffic and affordable housing and experienced local real estate agents can be an invaluable source of information on these dynamic conditions and they will know where available short term leases may be obtained.
For your reference, here are some Camp Pendleton billeting reference pages below.