Great topic, Steve.  This is a fine example of a reasonably possible survival scenario.  It doesn't always have to be "Robinson Crusoe" or a plane crash in the Andes.
Like any challenging situation, the priorities should be 
1) Mindset
2) Tactics
3) Skill
4) Equipment
Mindset: "I will plan ahead, and I will survive!"
Tactics: "Swim parallel to the beach to exit the current. Notify friends that I'll be out surfing"
Skill: "Be a fit and capable swimmer.  Know how to use basic signaling devices"
Some observations on 
Equipment:
- Buoyancy would be very desirable.  Perhaps consider using a boogie board that is tethered to your ankle.  Adapt your style because in a tough swimming situation, extra buoyancy would be very welcome.
- Signaling: signal mirror, bright & focused waterproof flashlight, whistle.  Maybe add a small strobe.  Very effective, light and small.  However you carry these small items, consider keeping them tethered on dummy cords made from de-cored 550 cord or something.  They would be easy to lose when you open your pocket while swimming in an emergency.  Consider having a cellphone in a   
waterproof case. 
- There are various models of drybag-style waist packs out there that you could use for a little extra gear.    
Here and   
here  are some examples. You might be able to surf with one of these and not attract too much attention.
- Do you do your surfing with goggles?  If not, consider toting a small pair and a noseclip to help prevent aspiration while swimming in choppy conditions.