Well, I have an advanced degree in physics and math from several decades ago.  I found I could follow about 10% of this opus, but continue to work on it anyway.  I'm determined to catch up on what I've been missing in physics, like how the standard model is justified.  Maybe should back up and study the Feinman lessons first, as a warmup.  Penrose is a genius, and does a great job of making these advanced ideas plausible to the general public, but you still have to have a good background in advanced math to follow his arguments.