It is actually not uncommon to pop the top part of the deck on these "shoebox design boats" and restore everything, re-install, etc. Happens all the time, have a ton of photos showing various projects under way. You pretty much outlined the tasks at hand, grind out the crazed areas, fill properly, sand with a flat block to get everything back to nice and flat, prime, sand, prime again, sand again, and then coat with an approved variety of paints including Awlgrip, Interlux Perfection-II, or equal. When they're finished up they look stunning.
There are MANY of these boats undergoing extensive restorations now, and I suspect we will see more and more of this in the future.
Here is an example of an early 23 Lancer that was brought back to show quality.........
Thanks to my friend, Eric, for the photos.