Even if dispensaries are shut down you will be able to get bud easily. People do private collective gardens where if you join you can donate/fund to the collective and in return you are able to receive some of the garden for yourself. Essentially how most dispensaries work.
Hell you can find weed on craigslist, but be careful lots of unflushed bud and thieves. Meet in public places first time, buy small, and try to test a bowl if you can before buying. Bowl over joint so you can make sure the bud does not sparkle showing unfurnished bud, or worse laced weed (I have only had this happen to me by a gangster dealing out of a storefront who was lacing meth on cannabis he bought from the club down the street (disgusting fucker) and a bitch whose dealer laced a small nug with HELLA coke... Or maybe freebase/crack). If they don't let you test it and get hostile over it or seemed rushed to get things done than it is probably crap weed.
Trust me get your card if your in cali and smoke weed a lot. It is a huge load off your shoulders, but not necessarily better priced weed. It is nice to be able to buy a wide variety of hash.
edit: Also on the state ID card it is not necessarily and only a state ID & doctors recommendation paper and some offices make cards. I have only had an issue when I was in a drug/social rehab program after a really stupid situation and they used a BS hospital report to call me cannabis addicted when it was more like oxymorphone/oxycodine and MXE use as well as an abusive family situation which was COMPLETELY ignored. They said I needed state ID, but someone else who went to this ADU program did not have the state ID and they did not go hard on her so even if they say it is needed they may just be lying to try to get you to let them forbid you from using it. In my situation I was supposed to be at the place for 2-3 weeks at most and they where telling me it takes at least 2 weeks to do it so I should just get used to not having cannabis and accept risperdal and benzos are avalible instead even though I was complaining about them taking me off a natural plant to put me on POWERFUL and addictive synthetic medication. Total complete abusive bullshit that was meant to cover a homeless services ass for making a mistake that left me homeless for 2 months and in the else lose my job. It is honestly is EXTREMELY difficult to get. My PH.d psychiatrist doesn't even know. I don't honestly know if it even really possible anymore. Hell my PM doc said he used to, but doesn't anymore as technically you can not "prescribe" cannabis on a federal prescription....
Essentially if the federal police (park rangers or other federal owned property security are some that you may not even think of) they can say fuck it we don't care about state law and only federal law and under that it is schedule 1 and cause you a lot of trouble no matter what identification. It will keep you safe in any state that has a medical cannabis law, but it can and will be trumped by any federal agent that cares to and possibly state agents.
edit: A good tip to find a good doctor. Look for one who has been prescribing for more than a year. If they have their licences at least renewed once it is a good sign.