I liked it. It's a very different book from The Shining and should be viewed as separate, but the key themes both books have in common is their oblique references to systemic oppression. In the earlier book, Jack's addiction is only one of the 'ghosts' haunting the Overlook, whereas the two big demons in Doctor Sleep are Dan's alcoholism and the notion of a group of liminal characters with the ability to suck the spirit out of people. You could make this stand in your head for a lot of facets of society; there are enough of them to choose from.
What I found intriguing about The Shining is the way in which it made me, as a reader, want to trace all the ghosts lurking in the empty hotel, just as Jack does in the basement of the Overlook with the scrapbook that's left for him to find. The text is 'haunted' at every turn by Edgar Alan Poe's 'Masque of the Red Death', but the masked ball is no less creepy in King's strange rewriting: who is its elusive host, Horace Derwent, other than than the 'real' villain of the piece? His mask never truly comes off; all we do know is that he's an exemplar of the entrepeneurial US 'gilded age' - apparently modelled on Howard Hughes - and a bisexual man who uses his male lovers as playthings then viciously holds them up for public ridicule. A piece of the puzzle the novel never gives us is the precise nature of Derwent's connection with the other, more shadowy and possibly even more menacing villain: Al Shockley. This is Jack's one-time drinking buddy, who has a definite interrelationship with both Derwent and America's rich and powerful elite, but he declines to enlighten Jack as to its nature or even existence, and neither Jack nor the reader ever find out what this is. The Kubrick film ignores him completely, but IMO a really threatening and ambiguous presence is removed by doing so. Wendy Torrance has a bit of a 'shine' herself therefore she isn't fooled: she hates Shockley from the start.
Then there's the gilded age itself. The Stanley/Overlook is a resort hotel harking back to that era - the rich, exploitative age that made colossal fortunes from the railroad, tobacco, oil and steel industries - and industries like this got fat off the exploitation of others. (Exploitation of America's resources and colonial history is a big theme in King). If anything, the Gilded Age itself is another sinister 'baddie', the very past on which the Overlook and its bloody, chequered history is built. It's strongly implied throughout the course of the novel that the Overlook was tainted from the moment it was built.
The Shining is a really nuanced text, not least in its uncanny aspects which could just as easily be psychological in the model of the classic Gothic tale. Doctor Sleep IMO doesn't replicate this - although oddly enough the film adaptation with its odd blend of the Kubrick predecessor and the book is a pretty decent piece of movie-making. The book is good and stands on its own merit (and may well have lots of similar analogies in it that I've missed), but I find The Shining the superior novel.