You always seem to have the words of wisdom! I had the regrowth and also found out that the scar tissue is the problem after the first surgery. My first tumor was huge and the scar tissue was very extensive. Interestingly, different neurosurgeons were afraid of the scar tissue at different sites. For some, it is at the entry point but not so much at the brainstem, for others, it is at the brainstem but not at the entry point. There were also very competent neurosurgeons who refused me by saying that they don't want to deal with any scar tissue the second time around and if they operated, I would have been guaranteed a poor outcome!
I investigated GK only so I cannot make any claims regarding CK. One of the neurosurgeons who does both radio- and micro- told me that GK can be done again and the surgery after GK is NOT more difficult. His criteria was no growth after two years and surgery if there continued growth after two years. I suspect that time after the radiosurgery might be an issue. The change in tumor texture is probably not instantaneous and happens over a period of years, so it becomes more difficult to operate seven years after the radiotherapy than two.
I wish I could follow your plan A!