Hello, I just moved to the Bay Area from upstate NY myself. It is my understanding that you have to either have a CA ID (not necessarily a drivers license) or a print out from DMV as a temp license or ID. You can visit the DMV's website for more info. And for more info on getting a rec here's a link to medicann

I just transferred my license and it cost me $28 and I had to take a 36 question written test (which you can take up to 3 times then you have to pay again). The print out you get from DMV is your temporary license with your old state license. This should be enough to get a rec from a doctor. I don't believe you can do anything without a print out from DMV either a temp license or a non driver ID. You don't need to get your car on the road or even have a car to transfer your license. But you do need to transfer your license within 10 days of moving to CA (or you could pay a penalty or have to take a road test) and you have to transfer the reg on your car within 20 days or pay a fee from 40%-160% the license and weight fees once you do depending on whether it's within the 1st or 2nd years or something like that.

Hope this helps. Have a great holiday and blessed be.