I just recently moved back to CA after living in Ohio for 5+ years. I went to the DMV and gave them an address that I have no legal ties to(but I can get mail there). Then I gave them my mailing address which is a UPS store 120 miles from the other address, which is the address they put on my license. I did not have to show proof that either of these addresses were mine. They then gave me my old license number. When I bought my FXT in April, I put the non-smog county address on the pink slip, but I used the DMV down the street from my mailing address in a smog county.