Nice job John!
I had a Martin 16 series that was a family heirloom too so replacing the side was not what the client really wanted. As others have said here I started with repairing and reinforcing the cracks and then went to patching.
What really helped me with the process and made it pretty easy too, just time consuming..., was using rare earth magnets for clamping cracks closed AND level and other reinforcements as well. Once you learn how to use these high-powered magnets safely avoiding how they can jump and even hurt you.... and once you understand that they will kill your I-Phone speaker too.... it was a positive experience.
Well done, that one was not easy by any measure, and she looks great today - good on you John!