Quick update. I made two new PCB designs and updated one older design I created from Altium Designer. I sent all three designs to OSHPark this past week.
Good news! Even though CS cannot open AD project files or PCB files, it can open the schematic SchDoc files from AD. Once I rounded up the correct libraries, I was able to make a new PCB rather quickly.
I am working on updating two other AD designs. One is lower priority and the other is more complex and the autorouter did some unexpected things. More details to follow soon.
OSHPark reports that all three designs are assigned to a panel and off to the fab. Should be less than two weeks to see the results.