This hike has a little of everything, terrain wise: Loose sand, packed sand, soggy sand, gravel, rock hopping, tide pools, bolder fields, two creek crossings, a steep slope scramble and a bit of chaparal. The sand/rock ratio will vary based on how high the tide and surf are. I wore tennis shoes and did just fine.
You might want to bring a bag or a pack along to carry back all the interesting rocks and pebbles you find along the way. If you don't, I can guarentee that your pockets will be stuffed by the time you get back to the car. The whole area is a geologist's paradise.
NOTE: There's no need to go atop the bluffs until you're within 250 feet of the cache. It's all Air Force property up there and there are no trails.
WARNING: There are fairly obvious pointy things within inches of the cache. Use care when removing and replacing the cache; it's a 40 mile drive to the nearest tetanus shot.