You'll want a backpack to put your finds in, and a good pair of shoes or sturdy hiking sandals to climb over the loose rocks. Take a water bottle and some lunch if you plan on going far.
Gaviota, Refugio, and El Capitan Beaches seem to have the best [and the most] material, although any beach in that area with enough rocks available will likely have pieces to pick up.
|Search among the cobbles for the bones|
|Petrified Wood from Gaviota|
On the field trip I attended, there were perhaps 40 lbs in total of petrified bone found, amongst ten or so people. It's far from rare, so you've got an excellent chance of finding some.
If you're wondering how to identify fossil whalebone when you find it, the key is all in the texture. It looks like little cells filled in with quartz or agate, as shown in the picture below.
It can come in all kinds of colors - I've found white, black, red, tan, and orange-yellow so far. Once you've found your first piece or two, you'll quickly develop an eye for it.
And, of course, remember not to get so focused on one kind of rock that you forget to look at the others. That petrified wood pictured above? Most of the field trip members walked right over it before I picked it up - but they were so focused on finding the bone, they never even noticed it.