So i'm thinking you'll be wasting a full day going around looking for a decent board and wetsuit ( and going back and finding it had already sold ). Then wasting another 1/2 to full day trying to hawk your board to some buyer. Plus if you haven't surfed a Fish before, your arms will be too sore to move the next day. So your 7 days of "surfing" might actually be more like 4 days.
You may also want to read this:
When Parked at a Public Park
Municipal codes govern city parks and each county will have its own set of laws. In San Diego, it is illegal to camp or sleep in any public park or beach. Thus, one cannot sleep in his car in a public park or beach in San Diego County. In Los Angeles County, camping is only allowed where designated, and then only in accordance with the rules and regulations governing the use of such area. In San Francisco, no person shall occupy any "house car, camper or trailer coach for human habitation." This includes sleeping, eating or resting on any street, park, beach or public way within the County of San Francisco between 10:00 p.m. and 6:00 a.m. County municipal codes can usually be found online at the specific county clerk's office website.
When Parked at a Public Rest Stop
According to the California Department of Transportation, it is legal to have your car parked for up to eight hours in a 24-hour period in a rest area. However, it is illegal to "camp or pitch a tent." If you are merely taking a nap under eight hours long, it is most likely legal. But, if you consistently sleep in the same spot or have any items outside the car, a judge or officer will most likely determine your activity is camping which is illegal. If your car is a larger van or RV then it may look more like camping to the officer in which case you could be told to leave, given a ticket or even arrested.
https://legalbeagle.com/12305435-illega ... ornia.html
) is my best option (planning on selling before leaving the US). 
