And if I remember correctly there are lockers just outside the Grizzley River Rapids (in CA Adventure) that you can use while riding that ride--without having to pay. I got soaked on that. LOL.
There has been some great suggestions for bags already so I will skip that.
Grizzley Rapids is my favorite ride. You get SOAKED!!!
I am not sure how many people will be in your party. But here is a little tip to save you LOTS!!!!!!! of time. Only if you are willing to split up.
I know for sure this works for the Rapids you can do single rider. Which means if there is an empty seat on one of the rafts they use single riders to fill it up. The only negative part of this is you do not get to ride with the rest of your party. It is worth it to me. Usually the line for this ride during the summer can be over 3 hours and there is not much shade. If you do the single rider I have never waited for more then 5 minutes.
I know they also do single rider on splash mountain. Another ride that the line can be over 3 hours and I have never waited for more then a couple of minutes.
I am pretty sure Splash Mountain is the only ride at Disneyland that does single rider I am not sure if more rides besides Grizzley does it at California Adventures.
How long will you be in the Los Angeles area? What other plans do you have? If you need any advise feel free to ask.