Re: Going to the coast (SoCal)
Given not every college has Spring Break at the same time, I don't think there is any one week that is better/worse than any other.
Disneyland and the freeways are always crazy year around.
And no, I would never recommend strolling around downtown. Although certain sections of downtown have been cleaned up a lot in the last few years. It's much safer than it used to be.
As for drumming:
Check out the Hollywood Guitar center with the Rock Walk. And right next door is the Sam Ash Drum department. Between the two, there is a ton of drum gear to drool over.
It is also worth hitting up The Professional Drum Shop (aka Pro drum) in Hollywood. It's not huge, it's a bit funky, but you can spend hours just looking at all the old photos tacked on the walls.
It's also worth looking to see who is playing at the Baked Potato when you are in town. Big name players are often doing side gigs at this tiny little club in North Hollywood.
And yes, many name players offer lessons when available. Even Gregg Bissonette has been advertising recently.