After watching the first episode of Knight of the Seven Kingdoms, I decided to read the novel first.
The first half of the episode follows it almost word to word, minus the defecation part.
The differences start with the sign-up for the tourney, in which the series add a lot of character, and the character of Baratheon. In the novel he’s very much a side character, mentioned twice.
The novel does focus a lot on Targaryens, and there are a lot of them too. Two prices, one with three sons, the other one with one. The entire story of heirs not fit for purpose is very much England history, as well as Baelor, ideal prince never to be king, is basically Black Prince, only Black Prince died from malaria.
The single bout Dunc has is quite realistic: instead of a story of an underdog beating more and more experienced opponents, we have a single fight, were Dunc can barely see or hear anything, and almost dies.