From my recollection (I’ve seen it several times but the museum is so big and beautiful sometimes everything blurs together…) it is of good size (not too big because of the winters, even in Itay). I am working from memory - I’ll check this later but I believe Cesare’s room was sumptuous (but of course) although it was not decorated by Raphaël. I believe when Della Rovere finally seized power and became pope he had many of the rooms, including some of the Borgia apartments, redecorated and painted by his contemporary masters, such as Raphaël.
Della Rovere was a high art aficionado and had exceptional taste. The Borgia apartments are incredibly sumptuous and tastefully decadent. Some are original to the time of Borgia. One example is the white marble window benches and fireplace -with the immortal words BORGIA and their papal bull carved into the marble forever. I lost 900 photographs I took in the Vatican, many of them were in the Borgia Apartments. Some thankfully were captured on my phone! I’ll post more soon!