Don't worry about the math. If you want to worry, worry about the foundational physics that he will address. I have "The Emperor's New Mind" and have plowed through parts of that over and over again, and I try to keep up with his lectures on the confluence of GR and quantum theory and how we might craft a convergence by letting go of some features of either model or both. I've got to get the "Road to Reality" but financial strains forbid that for now.
It is possible that gravitation does not follow the Newtonian model, nor the GR model. We don't know if that is true, and since gravitation is the big player on large scales, there is some question as to whether MOND (which has exhibited some predictive capacity) or other alternative gravitational models may gain some traction. In the Solar system (with the possible exception of the Pioneer probes), classical gravitational models seem to work OK. Once we get to galactic scales, MOND seems to work very well, but it is pretty ad hoc, and cannot cleanly explain the excess binding energy or excess lensing exhibited by clusters of galaxies. The really big questions at the foundations of physics, including the mechanics of gravitation, are up for grabs.