A dive at La Jolla Cove during the summer can be a pain in the A**...mainly due to the issue with parking. For mid-to-late October, you shouldn't have any problem with parking.
Logistically, just drop off all of your gear at the grassy area near the top of the stairs. You can have your buddy watch the stuff (or not) while you park your car nearby. In the summer, this can be several blocks away for free on-street parking.
Return to the grassy area and spread out your dive gear. Get geared up, walk down the steps, and do the dive.
In many years of La Jolla diving, I've never had an issue with anyone stealing anything from our "gear pile" while we are out diving. Nevertheless, I'd recommend not leaving anything of value on the grassy area while you dive. I carry my car key on a d-ring connected to my rig.
There is no dive shop in the Cove area. The closest place for air fills is OEX located in the La Jolla Shores area (about a 1.5 mile drive from the Cove). The staff there can be overwhelmed by kayakers, so you may want to go elsewhere for air fills. Sport Chalet at the La Jolla-UTC mall is the next closest dive shop. Ocean Enterprises in Clairemont Mesa will give a good, if not pricey, fill. I would have recommended SDUA for cheap air and nitrox fills...but they just closed their doors recently. I'm still broken up about that.
You can hire a local DM through Dive California or OEX. A better (and definitely more inexpensive) alternative might be to sign up on the Divebums.com email list-serv...and send out a "dive buddy wanted" post. There are many helpful local divers who would gladly take you out with them.
Hope this info helps...
