I think the truest statement I could write about this book is that it took me two weeks of plodding reading to get through. If it had been anybody other than King, I might have given up, but I have an incredible amount of respect for the man. There is nothing wrong technically with Doctor Sleep (hence my 3 star rating) but for me there was something missing and I can't quite but my finger on it.
I think it may have been that I found Danny Torrence sadly lacking - he was neither a hero nor an anti-hero. He came across just a little self-absorbed and ... boring. As the final AA moment reveals; even his 'terrible crime' was pretty 'meh'. There was no sublime beauty to his flawed character; no real psychological darkness after the events that took place in The Overlook. If it's a story about redemption then it came across as pretty uninspiring. (I far preferred Duma Key for that)
Abra was not likeable - I don't think this is necessarily a problem in a book as unlikeable characters can be interesting; Abra wasn't. I would have liked to have seen the relationship between Abra and Danny made more complex, more flawed; a temptation I think King came close to fulfilling but retreated from.
The True Knot would have been so much more frightening if it wasn't for that ridiculous tusk thing, which for me made them seem a little comical - they were far more sinister as O.A.P motor-homers, and with in-laws who come close to such (love you Ma & Pa), it added a delightful sense of wit. Rose the hat could have been glorious but sort of fell short.
The train was a totally missed opportunity - that whole idea of the ghostie people should have been run with. On the whole it was accomplished but far too restrained. It might have all been more forgiveable if it hadn't been the sequel to 'The Shining' but I really don't think I would have bothered with making Doctor Sleep part of that phenomenal legacy.