Someone on reddit got the novelization early and here are some tidbits I found interesting. Spoilers.
The novel starts with a dream sequence of an alternate timeline Luke. A Luke that dragged the droids out of the farm to give them to the Empire and lives in happy? boredom with Camie. So no wife, but this means he is not dreaming about any other wifes(?).
Hux would rather get rid of any old Imperial (here Edrison Peavey) straight away, they had their use in the past, but the FO has grown past them, according to Hux. Starfighters are at the ready, but only held back so Hux can show off his big gun.
Han made a Leia figure out of wood the night before the Battle of Endor. It is burned or used during a brief memorial for Han during the evacuation.
Rey is not worried about Luke: She’s good at two things. Salvaging broken things and waiting.
Toddler Kylo often played with the dice or showed it around in adoration of his father. Kylo would break stuff around the house with the Force while growing up. Leia and Han would worry behind closed doors, which Kylo did not like.
After the Galactic Civil War (OT trilogy) some new states formed. The FO shut some down as well as ‘hermetic kingdoms in the Unknown Regions’. Ofcourse we knew they conquered many planets there.
Luke only took padawans when he took Ben as apprentice. He thought he was ready then.
Luke wonders if he should be afraid of the pupil that wants to destroy him or the one that wants to be him.
Rey accesses Kylo’s powers, but Kylo finds Rey’s memories.
Luke explores the Cosmic Force after having reconnected with the Living Force. Rey is a clear instrument of the will of the cosmic force. He also finds Leia again in the Force. The will of the Cosmic Force was asleep after the end of the Sith and awoke during Luke’s exile. Living Force is the energy of life. Cosmic Force is the will of the universe.
Before Reylo handtouching scene. Luke: “Rey, you were right. I’m coming with you.”
Luke has donned the robes and lit the torch before several times and failed each time. Rey arrived after just such an attempt.
Luke and R2 searched for ancient lore for many years
Snoke muses about visions of the future in general and their interpretation. Be careful or die. He learned this when he was young and the galaxy was different. At an old age he knows how much is left out in visions.
Snoke has left legions of uncounted dead adversaries that underestimated him.
Snoke was an unexpected leader. The Imperials did not foresee that he would be the one. Not Rax, Sloane, the political fanatic Ormes Apolin or Brendol Hux. As potential leaders they were all co-opted, sidelined or destroyed. Only Armitage Hux (our general Hux) was left, who is a total tool.
The rise of the First Order was mostly improvisation, not a grand plan.
Snoke does not believe in Kylo anymore, he is a mix of light and dark, but unstable, will rethink his future after victory.
Snoke noticed Kylo’s surpise about the Force bond reveal, but then senses a calm and balanced Kylo. Kylo’s biggest flaw has been restored. Snoke thinks Kylo can only be great if he uses his power to steer his own destiny.
Kylo thinks that Rey leaving Kylo alive will be her demise.
Rey’s error was that she thought Kylo’s turn would be simple. He only rebelled against Snoke, but the future holds a range of possibilities.
Leia knows Luke is not there for real when they touch.
Hux only knows the fake story about the Jedi and the coup from ROTS. The FO’s child soldiers are the legacy of the Jedi and clone training regimes.
Luke thinks he hears the words ‘Let go Luke’ just before he vanishes on Ahch-To
Rey has no compassion for Kylo anymore and severed the connection between them.
Autumn changes to winter and the caretakers reminisce about earlier outsiders, kind and mad ones and long times without visits, but people keep coming. Rey will be recalled as Luke’s destructive and rude niece (earlier joke). The caretakers store Luke’s weapon (his saber or staff?) and star compass. Edit: Some of the things Luke brought actually came from Ahch-To originally.